The Journal of Volume 36 Number 3 September 2002 S Published by The Raptor Research Foundation, Inc. THE RAPTOR RESEARCH FOUNDATION, INC. (Founded 1966 ) OFFICERS PRESIDENT: Brian A. Millsap SECRETARY: Judy Henckel VICE-PRESIDENT: Keith L. Bildstein TREASURER: Jim Fitzpatrick BOARD OF DIRECTORS NORTH AMERICAN DIRECTOR #1: Philip Dllrich NORTH AMERICAN DIRECTOR #2: lAURiEj. Goodrich NORTH AMERICAN DIRECTOR #3: Jepf P. Smith INTERNATIONAl. DIRECTOR #1: Eduardo Inigo-Euas INTERNATIONA!. DIRECTOR #2: Ricardo Rodriquez-Estrella EDITORIAL STAFF EDITOR: James C. Bednarz, Department of Biological Sciences, P.O. Box 599, Arkansas State University, State University, AR 72467 U.S.A. ASSOCIATE EDITORS INTERNATIONA!. DIRECT OR #3: Beatriz Arroyo DIRECTOR AT LARGE #I : Jemima ParryJones DIRECTOR AT LARGE #2; Petra Bohall Wood DIRECTOR AT LARGE #3: Michael W. Collopy DIRECTOR AT I.ARGE #4: Carol McIntyre DIRECTOR AT I.ARGE #5: Robert N. Rosenfield DIRECTOR AT LARGE #6: Ed Henckel James R. Beltiioff Marco Restani Clint W. Boae Ian G. Warkenitn Joan L. Morrison Troy I. Wellicome Juan Jose Negro BOOK REVIEW EDITOR: Jeffrey S. Marks, Montana Cooperative Research Unit, University of Montana, Missoula, MT 59812 U.S.A. SPANISH EDITOR: Cesar Marquez Reyes, Instituto Humboldt, Colombia, AA. 094766, Bogota 8, Colombia EDITORIAL ASSISTANTS: Rebecca S. Maul, Joan Clark The Journal of Raptor Research is distributed quarterly to all current members. Original manuscripts dealing with the biology and conservation of diurnal and nocturnal birds of prey are welcomed from throughout the world, but must be written in English. Submissions can be in the form of research articles, short communications, letters to the editor, and book reviews. Contributors should submit a typewritten original and three copies to the Editor. All submissions must be typewritten and double-spaced on one side of 216 X 278 mm {SVz X 11 in.) or standard international, white, bond paper, with 25 ram (1 in.) mar- gins. The cover page should contain a tide, the author’s full name(s) and address (es). Name and address should be centered on the cover page. If the current address is different, indicate this via a footnote. A short version of the title, not exceeding 35 characters, should be provided for a running head. An abstract of about 250 words should accompany all research articles on a separate page. Tables, one to a page, should be double-spaced throughout and be assigned consecutive Arabic numer- als. Collect all figure legends on a separate page. Each illustration should be centered on a single page and be no smaller than final size and no larger than twice final size. The name of the author (s) and figure number, assigned consecutively using Arabic numerals, should be pencilled on the back of each figure. Names for birds should follow the A.O.U. Checklist of North American Birds (7th ed., 1998) or another authoritative source for other regions. Subspecific identification should be cited only when pertinent to the material presented. Metric units should be used for all measurements. Use the 24-hour clock (e.g., 0830 H and 2030 H) and “continental” dating (e.g., 1 January 1999). Refer to a recent issue of the journal for details in format. Explicit instructions and publication policy are outlined in “Information for contributors,”/. Raptor Res., Vol. 35(4), and are available from the editor. Submit manuscripts to J. Bednarz at the address listed above. COVER: Nestling Peregrine Falcon (Falco peregrinus) and selected feathers exhibiting schizochromism (see page 200). Painting by John Schmitt. Contents Population Status of Breeding Bald Eagles in Washington at the end of the 20th Century, James W. Watson, Derek Stinson, Kelly R. McAllister, and Thomas E. Owens 161 Response Distance of Ferruginous Pvgmy-Owls to Broadcasted CoNSPicinc Calls. Glenn a. Prandfoot, L. Beasnm, FeUpe Chavez-Rsunirez, and Jody L. Mays 170 Post-fledging Survival and Dispersal of Peregrine Falcons during a Restoration Project* LarMn a, Rowell, DanJ. CalverL Irene M.Barry, and Lowell Washburn 176 Morphology, CiMncs, and the Value of Voucher Specimens: An Exampie with (^riMTES Vulture. Carofe S, Griffiths and John M. Bates 183 Oral ADMiNisTRAitoN of TJutAmine/Zolazepam for the Immobilization of the Common pU^SARD (Bt^®p j^ Martin Jantmfcy, Thomas Ruf, and Wol%ang Zenker ...... 188 Hunting Behavior of and S^ace Use by Eastern Screech-Owls during the Breeding Season. Jenntfcr E. Bnbay and 194 Short CoMMUNiCAtioNs^^^^^^^^^^^^^^^^^ A David H. Ellis, Lynn W. Oliphan t, and James K- Fackicr 2CK) Natal DisratsAL of the CmiacarA (CaMcMia cmfmm) in Flortoa. Nicole M. Nemeth and Joan L. Mcffrison — 203 Recent Records of Crowned Eagles {HABPYHAiiAETUs comNATm) from Argentina, 1981-2000, M, Isabel Bellocq, Patricio Rsunirez-Llorens, and Julieta Filloy 206 New Observadons of the Pereorine Falcon (Falco ma:GRiNUS) in Peru. Mare Ki§ry 213 DNA PotTnaORFHisMS in Boreal Owls {AEcmius funereus) . Janne Beheim, Kauine Eldegard, Gro B^rmtad, Mats Isaksson, Geir Sonerud, Olav Heie, and Helge Klungland Post-fledging Movements and Foraging Habitats of Immature White-tailed Sea Eagles in the Nemuro Remon, Hokkaido, Japan. Saifco Shiraki Habitat Preferencis, Breemng Suc*^, and Diet of the Barn Owl ( Trro alba) in Rome: Urban WRSUS Rural Territories. Luca Salvati, Lamberto Ranazzi, and Alberto Manganaro Incidence of Nathbai j vfif ai f.i> FRactures in the Pectoral Bones of North American Accipiters. Aaron J. Roth, Gwrilym S. Jones, and Thomas W. French 229 Plasma Chemistry REEraffiNCE Valui^ in Free-fjving Bonelu’s Eagle {HmtAAETm fasciatus) Nestungs. Jarier Ralbonrin Mid Miguel Ferrer 231 Letters The Fox Kestrel {Faux> ajlopfjC) Hovers. Tiziano Londei 236 Probable Breeding of Short-eared Owls in Southern West Virginia. Frank K. Ammer and Petra Bohall Wood * 237 Endangered Egwiian Vulture {NmPHmN fercnoftervs) Entangled in Powerline Ground-wire Stabiuzer. Barred Forest-Falcon (MkmswR mmcoLUs) Predation on a Hummingbird. Tony Nunnery and MarkR.Welford 239 Book Reviews. Edited by Jeffiey S. Marks 241 218 220 224 The Raptor Research Foundation, Inc, gratefully acknowledges funds and logistical support provided by Arkansas State University to assist in the publication of the journal. THE JOURNAL OF RAPTOR RESEARCH A QUARTERLY PUBLICATION OF THE RAPTOR RESEARCH FOUNDATION, INC. VoL. 36 September 2002 No. 3 J Raptor Res. 36(3): 161-1 69 © 2002 The Raptor Research Foundation, Inc. POPULATION STATUS OF BALD EAGLES BREEDING IN WASHINGTON AT THE END OE THE 20TH CENTURY James W. Watson, ^ Derek Stinson, Kelly R. McAllister, and Thomas E. Owens Wildlife Program, Washington Department of Fish and Wildlife, 600 Capitol Way North, Olympia, WA 98501 U.S.A. AiiSTRAGT. — Erom 1980-98 the population of Bald Eagles (Haliaeetus leucocephalus) nesting in Washington increased {P < 0.001) at an exponential, annual rate of 10% as adult eagles reoccupied habitat vacated during the period of widespread persecution and DDT use. Further indications of population health were linear increases in the rates of nest occupancy, productivity, and nest success. Productivity and nest success of eagles affected by contaminants along Hood Canal and the Washington side of the Columbia River estuary also increased during the study period but remained below statewide averages. By 1998, the pop- ulation was widely distributed, with 89% of pairs nesting west of the Cascade crest, and 11% east of the crest. There were indications that the population stabilized from 1993-98, when statewide occupancy rates decreased {P = 0.040), and productivity and nest success stabilized. Modeling predicts that a statewide population of 733 breeding pairs at carrying capacity would, after 25 yr, provide an equilibrium population of 4913 eagles. Stability of the statewide population of Bald Eagles seems to be less dependent on pro- ductivity rates than on adequate numbers of replacement adults, as maintained through high survival. Key Words: Bald Eagle, Haliaeetus leucocephalus; breeding, population status, productivity, recovery; Washington. Status poblacional del aguila calva en reproduccion en el estado de Washington a finales del siglo 20 Resumen. — Desde 1980-98 la poblacion de aguilas calvas {Haliaeetus leucocephalus) en anidacion en Wash- ington ha aumentado (P < 0.001) en una tasa exponencial del 10% debido a la reocupacion del habitad vacante durante el periodo de persecucion directa y uso de DPT. Algunos indicadores adicionales de una poblacion saludable fueron el incremento linear en las tasas de ocupacion de nidos, su productividad y el exito de anidacion de las aguilas afectadas por los contaminantes a lo largo del canal de Hood y el costado del estuario del Rio Columbia el cual tambien aumento durante el estudio pero que permanecio por debajo de los promedios del estado. En 1998, la poblacion estaba ampliamente distiibuida, con 89% de las parejas anidando en el oeste de Cascade Crest y 11% al este. Hubo sintomas de que la poblacion se estabilizo desde 1993-98, cuando a nivel del estado, las tasas de ocupacion disminuyeron (P = 0.040) y la productividad y el exito de anidacion se estabilizaron. Un modelo elaborado establece que la poblacion a nivel del estado de 733 parejas en anidacion, a su maxima capacidad de carga, despues de 25 anos resultaria en una poblacion en equilibrio de 4913 aguilas calvas. Einalmente, la estabilidad de la poblacion a nivel del estado, de aguilas calvas parece ser menos dependiente las tasas de productividad que de los numeros adecuados del reemplazo de adultos mantenidos por un alta sobre vivencia. [Traduccion de Cesar Marquez] For the past 25 years, the population of Bald Ea- gles {Haliaeetus leucocephalus) breeding in Washing- ton has been extensively surveyed, researched, and managed in an effort to recover the species from ^ E-mail address: watson@valleyint.com state and federal threatened status. In the 1970s, 114 nesting pairs produced a mean of 0.75 young/ occupied territory (Grubb 1976). By 1985, the population had increased to 227 pairs, but produc- tivity remained below that of other populations (McAllister et al. 1986). Surveys since the 1980s 161 162 Watson et al. VoL. 36, No. 3 documented a further increase in the breeding population (Washington Department of Fish and Wildlife [WDFW], Heritage Data Base unpubl. data). The need to reevaluate the recovery status of the species prompted a review of the population (Stinson et al. 2001). Here, we report the results of that assessment for breeding eagles in Washing- ton, including an analysis of nesting success, pop- ulation numbers, and distribution. To simulate the consequences of environmental perturbations on the stability of the nesting population, we model population size and structure at carrying capacity under various vital rate regimes. Methods During 1980-92, statewide Bald Eagle nest occupancy was assessed from airplane surveys conducted in early April, and productivity from helicopter surveys in early June (McAllister et al. 1986, Watson 1993). From 1993- 98, biologists visited all historic nests each year during occupancy surveys, but did not conduct comprehensive productivity surveys. During that period, limited funding and volunteer efforts resulted in the documentation of nest success and productivity for a non-random sample of 28-47% of occupied territories each year. We are un- aware of any overt biases in the non-random samples due to changes in survey technique (i.e., air vs. ground), dis- tribution of sites surveyed, or changes in surveyors, that might have affected parameter estimates. We estimated three parameters from survey informa- tion, including (1) nest occupancy — the proportion of territories with one incubating adult or two adults at the nest; (2) nest success — the proportion of occupied ter- ritories producing at least one young; and (3) productiv- ity — the mean number of young raised to pre-fledging age (^8 wk) per occupied territory. We analyzed trends of these parameters by fitting them to linear models with simple linear regression. We determined statewide trends for (1) all years from 1980-98, (2) 1993-98 only (the period of nonrandom sampling), and (3) two regional populations, the Columbia River estuary and Hood Ca- nal, that experienced depressed productivity during the survey period (Anthony et al. 1993, WDFW Heritage Data Base unpuhl. data). Estimates of nest success in raptor populations are sub- ject to sampling errors when pairs that fail early in the nesting season may not be discovered and counted, lead- ing to the overestimation of productivity/ occupied site (Steenhof and Kochert 1982, Steenhof 1987). Because our surveys were potentially subject to this bias, we used a second method to calculate productivity recommended by Steenhof (1987). This method calculates productivity as the product of the proportion of pairs that bred, the pioportion of pairs that were successful, and the number of young/successful pair. Each parameter is estimated from a specific population subsample: proportion of breeding pairs from a preselected sample that includes only nests from the population that bred the previous year; proportion of successful pairs from all nests sur- veyed twice (i.e., during incubation and pre-fledging); and young/ successful pair from pairs identified in both early and late surveys. Proportion of successful pairs is not a direct computation, but is calculated with the May- field estimator (Mayfield 1961), which is the daily-nest- survival rate raised to the power of the length of the mean period that a nest is at risk of failing (Steenhof 1987). We used 93 d as the mean nest exposure period (McAllister et al. 1986). We did not determine trends in productivity estimated by the Steenhof method because calculations were based on combined parameter esti- mates that potentially biased sample variances (Steenhof 1987). We evaluated change in distribution of nesting eagles during 1980-98 by defining five broad ecoregions; the Olympic, southwest, and Puget Sound/Islands west of the Cascade Range, and northeast, and southeast ecoregions to the east (Fig. 1). The rate of population growth in each ecoregion was calculated from the number of oc- cupied territories documented in 1980 and 1998. We compared density of occupied nests <2 km from marine, lake, and large river shorelines between west and east ecoregions (Washington Rivers and Marine Shoreline data base, Wildlife Resource Data Systems, WDFW) . We estimated the number of statewide breeding pairs expected at carrying capacity by fitting population growth to a logistic curve based on the number of oc- cupied territories found each year from 1980-98. The logistic growth model is a simplistic model that assumes the population is approaching a steady density; age struc- ture is not considered, and all individuals are assumed to have an equal chance to give birth or die (Smith 1974). Thus, the model is not subject to changing survival and mortality rates. When a population grows exponentially, a linear relationship exists between the number of off- spring per parent and the sum of the densities of both generations (Morisita 196.5). The slope and intercept of this regression can be used to calculate the maximum intrinsic rate of population growth and carrying capacity as detailed in Caughley (1977) and Swenson et al. (1986). We determined these two parameters indepen- dently for eastern and western Washington because of habitat differences, and summed the numbers of terri- tories at carrying capacity for eastern and western Wash- ington to estimate the size of the statewide breeding pop- ulation at saturation. Because the logistic growth model did not address habitat limitations to the population, such as nest site availability, we assessed tbe reasonable- ness of the estimates of carrying capacity in light of visi- ble signs of population stability (i.e., increased incidences of urban nesting and fatal encounters of territorial adults with conspecifics), and a subjective estimate of the point at which the growth would reach an asymptote. At satu- ration, higher nest density might result in reduced nest- ing success because of closer distances between adjacent ne.sting pairs (Anthony et al. 1994). We used logistic re- gression to examine the effects of nearest-neighbor dis- tance on eagle occupancy, activity, and nest success in 1992, when the population showed signs of reaching sat- uration. Beyond a certain point, the actual number of nesting pairs at carrying capacity does not affect population sta- bility because its true indicator is age and stage structure at equilibrium (Hunt 1998). Thus, the deviation between September 2002 Bald Eagle Status in Washington 163 Figure 1. Distribution of Bald Eagle nests in Washington State among five ecoregions in 1980 (top) and 1998 (bottom) . future and predicted number of nesting pairs at carrying capacity was inconsequential to models of population sta- bility. To estimate population structure and stability at carrying capacity we used a modeling approach based on Moffat’s Equilibrium (Hunt 1998). Whereas traditional population modeling emphasizes density-dependent mechanisms that regulate population growth, modeling based on Moffat’s Equilibrium focuses on an adaptive limit to breeding site serviceability that restricts cohort size per unit area of landscape and consequently limits the size of the total population (Hunt 1998, Hunt and Law 2000). Causal regulation is considered modulating. Model parameters include the number of serviceable breeding locations (SBLs) at saturation (calculated from logistic modeling), age-specific survival rates, maximum longevity, and productivity. We used equations and rou- tines from Hunt (1998) to calculate age class sizes, floater to breeder ratios, and total population size at population 164 Watson et al. VoL. 36, No. 3 Table 1. Productivity characteristics of the Bald Eagle population in Washington State from 1980-98. Standard errors are shown with summary means. No. Percent of Pairs Percent of Pairs No. Young/ Occupied Terri- Breeding Successful Territory TORIES No. (%) No. Young/ SuR- Territories Successful Year VEYED Occupied Direct® Sampit/ Direct® Sample‘s Teriutory Direct® Sample‘S 1980 154 105 (68) 90 94 64 52 1.40 0.90 0.68 1981 165 126 (76) 97 97 56 37 1.35 0.75 0.48 1982 189 138 (73) 88 90 55 40 1.35 0.74 0.49 1983 231 168 (73) 92 94 49 47 1.47 0.86 0.64 1984 254 206 (81) 95 96 67 58 1.44 0.95 0.80 1985 290 231 (80) 88 88 65 60 1.50 0.98 0.80 1986 301 250 (83) 94 96 73 66 1.54 1.11 0.97 1987 327 268 (82) 93 94 65 54 1.49 0.98 0.75 1988 361 309 (86) 92 93 66 56 1.50 0.98 0.78 1989 424 369 (87) 91 93 63 55 1.62 0.99 0.83 1990 477 403 (84) 93 93 70 61 1.63 1.07 0.92 1991 515 445 (86) 91 92 63 52 1.57 0.97 0.76 1992 560 468 (84) 94 94 69 61 1.47 0.99 0.85 1993 588 493 (84) 95 95 63 53 1.52 0.94 0.76 1994 636 547 (86) 93 94 70 65 1.49 1.02 0.91 1995 660 558 (85) 95 95 63 49 1.50 0.90 0.69 1996 709 594 (84) 92 93 64 56 1.41 0.93 0.73 1997 727 582 (80) 95 95 66 50 1.53 0.97 0.73 1998 841 666 (79) 91 93 74 65 1.49 1.10 0.91 Total 8409 6926 (81 ± 1) 93 ± 1 94 ± 1 65 ± 1 55 ± 2 1.49 ± 0.02 0.95 ± 0.02 0.76 ± 0.03 ' Direct measurements based on entire population. Sample estimate from territories occupied the prior year (Steenhof 1987). ‘ Sample estimate calculated by the Mayfield Method (Steenhof 1987) from pairs surveyed twice. Steenhof (1987) estimate of productivity = (% breeding from sample) (% successful from Mayfield) (No. young/ successful pair) equilibrium based on a maximum eagle longevity of 25 yr This was greater than the 16-yr longevity estimated for eagles from the Greater Yellowstone Ecosystem (Harmata ct al. 1999), but less than the oldest documented Bald Eagle longevity record of 28 yr (Schempf 1997). Annual survival rates of adults (0.88), subadults (0.95), and ju- veniles (0.71), and productivity of 0.86 young/pair, were used in calculations, and were based on survival and pro- ductivity of 159 telemetered eagles and 622 occupied nests from Prince William Sound, Alaska (Bowman et al. 1995), where habitat is somewhat similar to that of coastal Washington. In any case, our interest was not so much in determining the accuracy of these statistics, but rather how changes in their values affected population stability. We modeled effects of hypothetical environmental per- turbations on population size and structure by reducing the number of SBLs, the productivity rate, and age-spe- cific survival. The barometer of population stability was the ratio between floating and breeding adults (F:B ra- tio) , with negative ratios indicative of inadequate recruit- ment and population decline (Hunt 1998). Re.su ITS From 1980-98, the annual occupancy rate of Bald Eagles in Washington averaged 81% and in- creased linearly (r = 0.62, F = 0.005; N = 8409 surveyed territories; Table 1); productivity aver- aged 0.95 young/occupied territory (N = 6926) and increased linearly (r — 0.52, P — 0.024); and nest success averaged 65% at occupied territories and increased linearly (r = 0.50, P = 0.031). How- ever, for the 1993-98 sample of territories (N = 4161), annual occupancy rates declined by 1.3% per yr (r = 0.83, P = 0.040), and there was no trend in nest success (P — 0.282) or productivity (P — 0.306) at territories that were surveyed non- randomly (N = 1397). Between 1980-98 the num- ber of Bald Eagle territories in Washington in- creased from 154-841 (Table 1). The number of pairs that nested each year increased logistically at a mean rate of 10.1% per yr ([log e] occupied ter- ritories = 4.850 + 0.101 yr; r = 0.98, P< 0.001). Sample estimates of statewide eagle productivity averaged 0.19 young/yr less than direct productiv- ity measures (Table 1). Much of this difference was September 2002 Bald Eagle Status in Washington 165 due to the Mayfield estimator for percent of suc- cessful pairs, which averaged 10% less than direct measures from the entire population. The percent of eagle pairs breeding in the preselected samples of pairs successful in the previous year averaged only 1% higher than direct measurements for the entire population from 1980-98. Between 1980-98, the Bald Eagle population nesting on Hood Canal increased from 3-33 pairs, and the population along the Washington side of the Columbia River estuary increased from 1-24 pairs. The annual occupancy rate on Hood Canal (82%; N — 398 surveyed territories) was similar to the statewide rate, but lower on the Columbia Riv- er estuary (69%; N = 328 surveyed territories). Productivity parameters of these populations were below statewide means (Table 1). Hood Canal ea- gles produced 0.63 young/occupied territory (N — 323), with 43% of nesting attempts at occupied ter- ritories successful. Eagles along the Columbia Riv- er estuary produced 0.56 young/ occupied territory {N = 277), and 41% of nesting attempts at occu- pied territories were successful. Despite the poor reproductive history of these populations, produc- tivity increased linearly from 1980-98 on Hood Ca- nal (r — 0.55, P — 0.016) and the Columbia River estuary (r = 0.68, P — 0.001), as did nest success (Hood Canal r = 0.59, P = 0.008; Columbia River estuary r = 0.81, P < 0.001). A notable change in the statewide distribution of nesting Bald Eagles from 1980-98 occurred east of the crest of the Cascade Range where the num- ber of territories increased from 0—59. Eifty-four of these territories (92%) were located in the north- east ecoregion, primarily along the upper Colum- bia, Spokane, and Pend Oreille rivers (Fig. 1). West of the Cascade Crest, the increase in number of nesting territories was similar among the Olympic ecoregion (380%, N — 54-259), Puget Sound ecoregion (350%, N — 90-405), and southwest ecoregion (292%, N = 13-51). The increase in number of occupied territories was greater in southwest Washington (829%, N = 7-65), than in Puget Sound (475%, N — 61-351) and the Olym- pic ecoregion (438%, N = 37-199), a difference largely due to reoccupancy of vacant nests along the Columbia River estuary. In westside ecoregions there was a progressive expansion of nesting pairs inland to major rivers and lakes along the coast and Puget Sound (Fig. 1). In 1998, the mean den- sity of occupied Bald Eagle nests <2 km from 6416 km of forested, marine shorelines in western Wash- ington was 1 nest/ 10.4 km. In eastern Washington, density was 1 nest/34,6 km along 1728 km of in- land waters. We did not detect any relationship be- tween nearest-neighbor distance and nest occupan- cy (P = 0.534), activity (P = 0.173), or success (P = 0.650) at 560 territories in 1992. Logistic population growth modeling based on the assumption that the population was approach- ing a steady density, projected an ecological car- rying capacity of 639 nesting pairs in western Wash- ington, and a maximum growth rate of 9.5%. The model yielded a carrying capacity of 94 pairs in eastern Washington, and a maximum intrinsic growth rate of 16.7%. The combined total for nest- ing pairs (733) was used as the statewide number of SBLs, in our modeling exercise which predicted a population of 4913 eagles at Moffat’s Equilibrium (25 yr after the population reaches carrying capac- ity). The stable population consisted of 1907 sub- adults and juveniles, 1540 floating adults, and 1466 breeding adults, resulting in an F:B ratio of 1.05. When other parameters were held constant, F;B ra- tios of the predicted population were reduced to a critical level (i.e., <0) resulting in population de- cline when adult survival declined 17% (0.88- 0.73), or subadult survival declined 22% (0.95- 0.74), or juvenile survival declined 52% (0.71- 0.34), or productivity declined 52% (from 0.86- 0.41 young/ pair) . In a hypothetical scenario where productivity and juvenile age classes were primarily impacted (e.g., nest disturbance, contaminants) the population declined when productivity rates and juvenile survival were each reduced by 31%. However, in a scenario where survival of all age classes was impacted (e.g., oil spill, prey crash) the population declined when adult survival was re- duced by only 7%, subadult survival by 8%, and juvenile survival by 10%. In a scenario where the number of statewide SBLs was reduced by 50% and survival and productivity rates were maintained (e.g., habitat loss from development), the equilib- rium model predicted a 50% reduction in the size of each age class and total population when the population stabilized, but the F:B ratio remained at 1.05, a condition conferring a high degree of population security. Discussion Population Growth. Exponential population growth exhibited by the Bald Eagle population in Washington in the past 20 yr surpassed that within the contiguous United States as a whole (i.e.. 166 Watson et al. VoL. 36, No. 3 384%, N = 1188-5748 occupied territories; U.S. Fish and Wildlife Service unpiibl. data) . Although intense habitat management and protection of nest territories in Washington occurred during that period, including the development of 1150 ea- gle habitat management plans with state and pri- vate landowners (WDFW Wildlife Resource Data Systems unpubl. data) , population growth was most likely a direct consequence of (1) reduced perse- cution that decimated the population beginning in the early 1900s (Dawson and Bowles 1909) and (2) reduced environmental levels of DDT, the insecti- cide that caused eggshell thinning and embryo mortality and was believed to have drastically re- duced eagle populations after 1945 (Stalmaster 1987). Use of DDT was banned in 1972, eight years prior to our study. Increased rates of nest success and productivity that we documented would be ex- pected when contaminants levels declined in eagle habitats, eagle prey, and ultimately breeding adult eagles that were also under reduced threats of di- rect persecution. This would be followed by in- creased occupancy of vacant nests at historic sites as more individuals reached maturity and the pop- ulation increased. We found population increases even among contaminant-impaired eagle popula- tions on the Columbia River estuary and Hood Ca- nal. Although productivity remained below state- wide means for those populations, it increased significantly in the past 20 yr. At their present den- sities, the contribution of these regional popula- tions to the number of nesting pairs in Washington is minor (i.e., in 1998 only 4% of nesting pairs in the state were on the Columbia River estuary, and 5% on Hood Canal), but these populations are nevertheless important as local bio-indicators of contaminant levels (Anthony et al. 1993). Rapid repopulation of nesting habitat by Bald Eagles was in part related to the tendency of off- spring to return to natal regions (Wood 1992, Dris- coll et al. 1999, Harmata et al. 1999). Evidence from Montana suggests non-breeding male Bald Eagles exhibit fidelity to geographically small natal areas that are familiar to them (e.g.. Greater Yel- lowstone Ecosystem population), whereas many fe- males disperse more widely (Harmata et al. 1 999) . In Washington State, we have no data to indicate that breeding eagles from western Washington cross the Cascade Mountains and pioneer new ter- ritories in eastern Washington, although the Cas- cade crest is no hindrance to movement of winter- ing eagles (J. Watson unpubl. data). The more rapid growth in eastern Washington compared to the west side suggests carrying capacity for nesting eagles will be reached sooner in western Washing- ton. The density of nesting Bald Eagles in eastern Washington is presently half of that in western Washington based on available shoreline, but the amount of difference due to lower prey and nest tree densities is unknown, as is the density the east side eagle population may reach at saturation. A density of 1 nest/ 11 river km is reported along the upper Columbia River in southern British Colum- bia to the north of eastern Washington (Blood and Anweiler 1994). Population Equilibrium. The logistic growth model, our examination of trends in nesting pa- rameters from 1993-98, and recent occupation of eagle territories in urban areas all indicate that the population of breeding eagles in Washington is ap- proaching saturation. Equilibrium theory predicts that as competition for the limited number of SBLs increases within a population, increased interfer- ence from floating adults for prey and nest sites should reduce productivity and survival (Haller 1996, Hunt 1998). Indeed, in Washington during the past 5 yr at least six fatal encounters between floating adults that attacked breeding adults have been documented, whereas prior to that time no similar events were reported (J. Watson unpubl. data) . The linear decrease in nest occupancy, and stabilization of productivity and nest success of Bald Eagles in Washington during the 1990s are consistent with predicted modulating effects of floater pressure following population saturation (Hunt 1998), a phenomenon also documented in other Bald Eagle populations (Hansen 1987, Bow- man et al. 1995). Our surveys of the subpopulation of Bald Eagles nesting in the San Juan Archipelago of northwest Washington (i.e., 90 territories) show the number of occupied territories declined by <10% in the years following a peak in 1994 (Fig. 2). This may indicate the range of population de- cline to be experienced throughout Washington from the density-dependent effects of floater inter- ference. The occupancy rate of Washington Bald Eagles is unlikely to increase from present levels to high levels such as reported in Arizona (i.e., 90%, Driscoll et al. 1999), because many of the unoc- cupied territories have degraded habitat, excessive levels of disturbance, or may be limited by prey availability ( J. Watson unpubl. data) . Nevertheless, a small but increasing number of Bald Eagles in Washington demonstrated surprising tolerance to September 2002 Bald Eagle Status in Washington 167 Year Figure 2. Growth of the Bald Eagle population in the San Juan Islands in northwest Washington. Data for 1962-79 from Nash et al. (1980), and for 1980-98 from WDFW (unpubl. data). human activity in the 1990s (Watson et al. 1999) and established new territories in urban parks, neighborhoods, and golf courses. The estimated productivity level of 0.95 young/ occupied territory, the recent decline in nest oc- cupancy, and stabilization of productivity and nest success rates, provide further evidence that the Washington population of nesting Bald Eagles is at saturation. However, the effects of incomplete, non-random surveys on estimates of the latter pa- rameters is uncertain. In some cases Bald Eagle ter- ritories affected by management plans, and poten- tially having higher human disturbance levels, were given survey priority (S. Negri and S. Ament, pers. comm.), but productivity of such nests has not been found to be different from the general pop- ulation (G. Schirato unpubl. data). Early literature suggested productivity of 0.7 young/ nest was nec- essary for population stability (i.e., Sprunt et al. 1973). If survival is as high as reported elsewhere for juvenile and adult eagles, mean productivity of <1.0 young/nesting pair appears adequate for population stability (Buehler et al. 1991, Bowman et al. 1995, Harmata et al. 1999). Our direct esti- mate of statewide productivity in Washington (0.95 young/occupied territory) is within that range. Even if the sampling method more accurately re- flects true productivity of Washington eagles (0.76 young/occupied territory, 20% lower than direct estimates) , either survival rates are high enough to sustain such rapid population growth, or the Wash- ington population is being supplemented substan- tially by immigration from other populations, or both. We suspect productivity estimates from the sampling method were unrealistically low, because in Washington locations of virtually all Bald Eagle nests were well-documented and nests were highly visible from the air. This increased the likelihood of encountering adults to conbrm activity even at failed nests or those where no eggs were laid, so we believe that few early nest failures were missed. Population Stability. Predictive models based on equilibrium theory provided a prioritization of population parameters for their relevance to main- taining population stability during hypothetical en- vironmental perturbations. While the eventual size of the Bald Eagle population in Washington will be limited by the number of SBLs, maintaining an ad- equate ratio of floating to breeding adults is the ultimate determinate of population stability (Hunt 1998). Ideally, the population of floating and breeding adults could be surveyed simultaneously on a periodic basis to assess population stability. In Washington, floating adults may spend up to 40% of the year in Canada and southeast Alaska from June-November (J. Watson unpubl data). Surveys conducted in spring in Washington could allow an accounting of breeders on territories and provide an estimate of floating adults, but might be im- practical because of costs. Therefore, the most im- portant emphasis for maintaining the eagle popu- lation is to maximize survival, and prevent or ameliorate environmental factors that result in di- rect mortality (e.g., shooting) or indirect mortality (e.g., lead poisoning) of adults, and secondarily subadults, during their 3-yr transition to adult- hood. The ratio of floating to breeding adults was least sensitive to changes in rates of productivity and juvenile survival, so these are the least impor- tant parameters to population stability. Dramatic declines in eagle productivity or juvenile survival (i.e., 50%) would have to be experienced to pro- duce the same effects as small declines in the sur- vival of older birds (e.g., 7-10% for adults). This corroborates Grier’s (1980) conclusion that popu- lation dynamics of Bald Eagles depend more on survival than reproduction. Reproduction has more often been the parameter monitored to de- termine Bald Eagle status because it is a sensitive indicator of contaminant problems and it is also easier to monitor than eagle survival (Harmata et al. 1999). The equilibrium model suggests that de- termining a minimum number of SBLs needed to maintain population stability in Washington 168 Watson et ai.. VoL. 36, No. 3 should be based on what number is necessary to provide an overall reserve of nonbreeding adults adequate to buffer fluctuations in density-indepen- dent mortality factors (e.g., weather, electrocu- tions, oil spills) . The optimum number of SBLs in Washington State, however, must be determined af- ter consideration of aesthetic values of Bald Eagles; the public may, for example, desire to protect more territories than necessary for population sta- bility. Current management of breeding Bald Ea- gles in Washington as directed by state legislation is to manage all territories equally on state and pri- vate land regardless of habitat quality. Our popu- lation model suggests the ultimate need to con- serve the population is to protect the quality breeding habitats for a target number of territo- ries, whether greater or less than the 733 projected territories, and thus ensure a stable number of breeding locations into the foreseeable future. Pri- oritization of existing territories for protection based on their distribution, the condition of habi- tat, threats to the habitat, and proximity to forag- ing areas is an objective of Bald Eagle recovery in Washington (Stinson et al. 2001). Acknowitdgments We thank G. Hunt for introducing us to the equilibri- um model. He and K. Steenhof provided insightful dis- cussions and comments on population estimates and modeling. C. Dykstra and F. Isaacs provided excellent comments that improved an earlier manuscript. Biolo- gists with the WDFW conducted the majority of surveys throughout the years of this study including S. Ament, D. Anderson, J. Bernatowicz, E. Cummins, T. Cyra, M. Davison, L. Hofmann, L. Leschner, A. McMillan, P. Miller, R Milner, S. Negri, G. Schirato, L. Stream, M. Zahn, and S. Zender. Other organizations contributed substantial h- nancial or survey support including the U.S. Fish and Wildlife Service, U.S. Forest Service, the Weyerhauser Company, and Puget Power. We especially thank biolo- gists R. Anderson, G. Walter, M. Murphy, M. Stalmaster, E. Taylor, and U. Wilson for their survey contributions. Data base assistance was provided by J. Stofel, and graph- ics support by J. Talmadge. Literature Cited Anthony, R.G., M.G. Garrett, and C.A. Schuler. 1993. Environmental contaminants in Bald Eagles in the Columbia River estuary./. Wildl. Manage. 57:10-19. , R.W. Erenzel, F.B. Isaacs, and M.G. Garrett. 1994. Probable causes of nesting failures in Oregon’s Bald Eagle population. Wildl. Soc. Bull. 22:576-582. Blood, D. and G.G. Anweiler. 1994. Status of the Bald Eagle in British Columbia. Wildlife Working Report Number WR-62. Wildlife Branch, Ministry of Environ- ment, Lands, and Parks, Victoria, British Columbia, Canada. Bowman, T.D., P.F. Schempf, and J.A. Bernatowicz. 1995. Bald Eagle survival and population dynamics in Alas- ka after the Exxon Valdez oil spill. J. Wildl. Manage. 59:317-324. Buehler, D.A., J.D. Eraser, J.K.D. Seegar, G.D. Therres, AND M.A. Byrd. 1991. Survival rates and population dynamics of Bald Eagles on Chesapeake Bay. J. Wildl. Manage. 55:608-613. Caughley, G. 1977. Analysis of vertebrate populations. John Wiley and Sons, New York, NY U.S.A. Dawson, W.L. and J.H. Bowles. 1909. The birds of Wash- ington State. 2 Vols. Occidental Publishing, Seattle, WA U.S.A. Driscoll, D.E., R.E. Jackman, W.G. Hunt, G.L. Beatty, J.T. Driscoit, R.L. Glinski, T.A. Gatz, and R.I. Mes- TA. 1999. Status of nesting Bald Eagles in Arizona. /. Raptor Res. 33:218-226. Grubb, T.G. 1976. A survey and analysis of Bald Eagle nesting in western Washington. M.S. thesis, Univ. of Washington, Seattle, WA U.S.A. Grier, J.W. 1980. Modeling approaches to Bald Eagle population dynamics. Wildl. Soc. Bull. 8:316-322. Haller, H. 1996. Der steinalder in Graubenden. Der Or- nithologische Beobacter (Biheft) 9:1-167. Hansen, A.J. 1987. Regulation of Bald Eagle reproductive rates in southeast Alaska. Ecology 68:1387-1392. Harmata, A.R., GJ. Montopoij, B. Oakieaf, P.J. Har- MATA, and M. Restani. 1999. Movements and survival of Bald Eagles banded in the Greater Yellowstone Eco- system./. Wildl. Manage. 63:781-793. Hunt, W.G. 1998. Raptor floaters at Moffat’s equilibrium. 0^■Ao5 82:191-197. AND P.R. Law. 2000. Site-dependent regulation of population size: comment. Ecology 81:1162-1165. Mayfield, H.F. 1961. Nesting success calculated from ex- posure. Wilson Bull. 73:255-261. McAllister, K.R., T.E. Owens, I.. Leschner, and E. Cum- mins. 1986. Distribution and productivity of nesting Bald Eagles in Washington, 1981-1985. Murrelet 67: 45-50. Morisita, M. 1965. The htting of the logistic equation to the rate of increase of population density. Res. Popul. Ecol. 7:52-55. Nash, C.M., M. Pruett-Jones, and G.T. Allen. 1980. The San Juan Islands Bald Eagle survey. Pages 105-115 in R.L. Knight, G.T. Allen, M.V. Stalmaster, and C.W. Ser- vheen, [Eds.]. Proc. of the Washington Bald Eagle Symposium. The Seattle Aquarium, Seattle, WA U.S.A. Schempf, P.F. 1997. Bald Eagle longevity record from southeastern Alaska. / Field Ornithol. 68:150-151. Smith, R.L. 1974. Ecology and field biology. Harper and Row Publishers, New York, NY U.S.A. Sprunt, a. IV, W.B. Robertson, Jr., S. Postupalsky, RJ. Hensel, C.E. Knoder, and EJ. I TGAS. 1973. Compar- September 2002 Bai.d Eagle Status in Washington 169 ative productivity of six Bald Eagle populations. Trans. 3T^ N. Am. Wildl Nat. Resour. Conf. 31:190-200. Stalmaster, M.V. IQS'/. The Bald Eagle. Universe Books, New York, NY U.S.A. Steenhof, K. 1987. Assessing raptor reproductive success and productivity. Pages 157-170 in B.A. Millsap and K.W. Kline [Eds.]. Raptor management techniques manual. National Wildlife Federation, Washington, DC U.S.A. AND M.N. Kochert. 1982. An evaluation of meth- ods used to estimate raptor nesting success. /. Wildl. Manage. 46:885-893. Stinson, D.W., J.W. Watson, and K.R. McAllister. 2001. Washington State status report for the Bald Eagle. Washington Department of Fish and Wildlife, Olym- pia, WA U.S.A. Swenson, J.E., K.L. Alt, and R.L. Eng. 1986. Ecology of Bald Eagles in the Greater Yellowstone Ecosystem. Wildl. Monogr. 95. Watson, J.W. 1993. Responses of nesting Bald Eagles to helicopter surveys. Wildl. Soc. Bull. 21:171-178. , DJ. Pierce, and B.C. Cunningham. 1999. An ac- tive Bald Eagle nest associated with unusually close human activity. Northwest. Nat. 80:71-74. Wood, P.B. 1992. Habitat use, movements, migration pat- terns, and survival rates of subadult Bald Eagles m north Florida. Ph.D. dissertation, Univ. of Florida, Gainesville, EL U.S.A. Received 13 November 2001; accepted 19 April 2002 Associate Editor: Marco Restani J Raptor Res. 36(3):l70-l75 © 2002 The Raptor Research Foundation, Inc. RESPONSE DISTANCE OF FERRUGINOUS PYGMY-OWLS TO BROADCASTED CONSPECIFIC CALLS Glenn A. Proudfoot,^ Sam L. Beasom,^ Felipe Chavez-Ramirez,^ and Jody L. Mays^ Caesar Kleberg Wildlife Research Institute, Campus Box 218, Texas ACfM University— Kingsville, Kingsville, TX 78363 US. A. Abstract. — To assess the efficiency of broadcast surveys for Ferruginous Pygray-Owls ( Glaucidium hras- ilianum), we tested the response distance of nine, radio-tagged, adult males. We recorded vocalization and movement toward the broadcast station as separate types of responses. Response to broadcasted conspecific calls was tested for each pygmy-owl at distances from 250-700 m. Broadcasted calls elicited vocal response from all nine pygmy-owls tested at <550 m and eight of the nine pygmy-owls moved toward the broadcast station. At 600 m, eight responded vocally and seven of the nine pygmy-owls tested, moved toward the broadcast station. Of the six pygmy-owls tested at 700 m, four responded vocally and three moved toward the broadcast station. As we recorded a 100% response from a distance of ^550 m, the effective coverage of areas formed by establishing survey points from 400-1400 m apart, in 100 m increments, would range from 97.7-61.7%, respectively. For these same increments, broadcast overlap would range from 54.7-0.0%, respectively. Based on response distance information, researchers may choose between different survey levels. For example, to maximize detection, researchers may develop survey protocols that canvas an area with overlapping radii and redundant sampling. Antithetically, to determine general distribution of a species over expansive areas, researchers may choose to increase survey efficiency by reducing broadcast overlap, survey effectiveness, and redundant sampling. Key Words: Ferruginous Pygmy-Owl\ Glacidium brasilianum; broadcast survey. Distancia de respuesta de Glacidium brasilianum, a vocalizaciones emitidas de la misma especie Resumen. — Para evaluar la ehciencia de muestreos a traves de difusion de llamados para Glaucidium bra.silianum, probamos la distancia a la que respondieron nueve machos adultos con radio telemetria. Definimos vocalizacion y movimiento hacia la estacion de difusion como dos respuestas distintas. Res- puestas a llamados grabados de la misma especie se probaron a distancias de 250-700 m. Los llamados difundidos causaron respuesta vocal en los nueve tecolotitos probados a <550 m; ocho de los nueve tecolotitos probados a 550 m respondieron con vocalizacion, se movieron hacia la estacion de difusion. A 600 m, ocho de los nueve probados respondiernon vocalmente y siete de los nueve respondieron vocalmente y se movieron hacia la estacion de difusion. De seis tecolotitos probados a 700 m, cuatro respondieron vocalmente y tres se movieron hacia la estacion de difusion. Ya que obtuvimos una res- puesta del 100% a una distancia de 550 m, la cobertura efectiva de areas formadas al establecer puntos de difusion de 400-1400 m, en incrementos de 100 m, cubririan entre el 97.7-61.7%, respectivamente. Para los mismos incrementos el area de traslape de areas de difusion efectiva cubririan entre el 54.7- 0.0%, respectivamente. Al utilizar la informacion de distancia de respuesta investigadores podrian es- coger entre diferentes niveles de muestreo. Por ejemplo, para maximizar la deteccion de especies de interes, un investigador podria desarrollar protocolos que cubran toda el area con traslape de areas de difusion y hacer muestreo redundante. Sin embargo para determinar la distribucion general de una especie sobre areas extensas, un investigador podria decidir en protocolos de muestreo que incremente la eficacia de cobertura al reducir el traslape en el area efectiva de cobertura del area de difusion [Traduccion de los autores] ' Present address; Department of Wildlife & Fisheries Sciences, Room 210, Nagle Hall, Texas A&M University, College Station, TX 77843-2258 U.S.A.; e-mail address: gap9662@labs.tamu.edu Deceased Present address: International Crane Foundation, P.O. Box 447, Baraboo, WI 53913 U.S.A. * Present address; U.S. National Park Service, Padre Island National Seashore, P.O. Box 181300, Corpus Christi, TX 78480-1300 U.S.A. 170 September 2002 Response of Pygmy-Owls 171 Accurate survey methods are critical to the man- agement and conservation of threatened and en- dangered species. Survey methods can provide es- timates of distribution, relative abundance, habitat use, and with some species, sex ratios. These base- line data are important for evaluating the status and trends of species impacted by changing land- use practices and loss of suitable habitat. Measur- ing response of individuals to broadcasted conspe- cific calls is an important method employed for surveying avian populations (Allaire and Landrum 1975, Johnson et al. 1981, Smith et al. 1987, Stah- lecker and Rawinski 1990) . However, without defin- itive unbiased information regarding effective sam- pling area, broadcast surveys only provide an index of presence/absence (McLeod and Anderson 1998). The overall effectiveness of this method de- pends on several factors. First, responsiveness varies among species and seasonally within species (Springer 1969, McNicholl 1978). Second, terrain and other environmental factors (e.g., wind and precipitation) affects dissipation of sound waves and, thus, influences the maximum distance from which a response can be elicited (DeMaso et al. 1992) and answering calls can be heard. Third, the distance between sample points determines the de- gree of overlap among broadcast radii. Hence, the distance between sample points influences the po- tential for redundant sampling to occur, such that if the distance between sites is too small, individu- als can be counted multiple times, providing over- estimates of abundance or population size. In the United States, the Ferruginous Pygmy-Owl {Glaucidium brasilianum) only occurs in southern Texas and southwestern Arizona. In Arizona, it is currently listed by the U.S. Fish and Wildlife Ser- vice (1997) as endangered. This species is a cavity nester that requires mature trees, including large columnar cacti for nesting, and an adequate prey base (Proudfoot and Johnson 2000) . Throughout Arizona and Texas, pygmy-owl populations are fragmented by islands of suitable habitat (Ober- holser 1974, Millsap and Johnson 1988, Proudfoot and Johnson 2000) . The determination of popu- lation sizes and distributions are essential data for assessing population viability and the identification of critical habitat. As a case in point, information from broadcast surveys used to estimate density and distribution of pygmy-owls in Texas suggest a viable population occurs in Kenedy County (Wauer et al. 1993, Mays 1996). Information provided from these surveys was undoubtedly a key factor in the final decision of the Service not to list the pygmy- owl as threatened in Texas (U.S. Fish and Wildlife Service 1997). These survey data were collected and interpreted without information on the terri- tory size of this species and the distance at which pygmy-owls would respond to broadcasted conspe- cific calls. Hence, the frequent clustering of re- sponses that occurred within the live oak-honey mesquite {Quercus virginiana-Frosopis glandulosa) forest (Wauer et al. 1993, Mays 1996) may have been the result of redundant sampling of individ- uals. Mays (1996) established broadcast stations 400 m apart along road transects in the initial sur- vey and used a 400 m minimum to determine ran- dom placement of broadcast stations during her repeated survey effort. Wauer et al. (1993: 1072) used modified Emlen (1977) method and U.S. Fish and Wildlife Service Breeding Bird Survey method to conduct broadcast surveys. He provided no spe- cific information about how the two methods were employed (e.g., distance between broadcast sta- tions). Information obtained during a pilot study to ascertain the response distance of pygmy-owls (i.e., two radio-tagged pygmy-owls were recorded responding at 600 m from the broadcast station) prompted Mays (1996) to urge caution be used when interpreting survey data collected along tran- sects with survey points established ^400 m apart. In January 2000, the U.S. Fish and Wildlife Ser- vice (2000) issued a standard protocol to be used for surveying areas that were proposed for future development within boundaries designated as crit- ical habitat for pygmy-owls in Arizona. Although the protocol was based on data provided in the available literature and from information submit- ted by scientists and non-scientists during the pub- lic-comment period, the U.S. Fish and Wildlife Ser- vice (2000) did not support the protocol with research results or information documenting effec- tiveness. Hence, as was the case with Wauer et al. (1993) and Mays (1996), the survey protocol cur- rently employed in Arizona may provide a biased measurement of pygmy-owl abundance. The objec- tive of this paper was to provide information re- garding the response distance, vocal and move- ment, of pygmy-owls to broadcast conspecific calls. We suggest that this information be used in the development of survey protocols that assess pygmy- owl distribution and long-term population trends accurately. 172 Proudfoot et al. VoL. 36, No. 3 Study Area and Methods Research was conducted within 29 000 ha of live oak- honey mesquite forest in Kenedy County, Texas, the same forest in which Wauer et al. (1993) and Mays (1996) con- ducted surveys to estimate population numbers for pygmy- owls in Texas. Climate was subtropical with 68 cm and 24°C of mean annual precipitation and temperature, respective- ly Elevation of the study area ranged from 5-21 m. Nine adult male pygmy-owls (four in 1995 and five in 1996) were trapped during the nesting season (April and May; Proudfoot and Johnson 2000), fitted with transmit- ters, and monitored for 7-10 d prior to testing. Because spontaneous calling (bouts) of pygmy-owls are usually crepuscular (Gilman 1909, Proudfoot and Johnson 2000), testing was restricted to 30 min before and after sunset, as determined by the U.S. Naval Observatory, Washington, DC U.S.A. (http://mach.usno.navy.mil/ cgi-bin/ aa_rstablew.pl). Testing was not conducted when winds exceeded 24 kph or when precipitation occurred (Proudfoot and Beasom 1996). Our testing was limited to <700 m, because when es- tablishing the protocol for conducting call count surveys for Northern Bobwhites {Colinus virginianus) , DeMaso et al (1992) determined 700 m was the apex for surveyors to detect calls at 60-70 decibels (db), a similar acoustical level as produced by pygmy-owls. Two male pygmy-owls elicited by researcher’s vocal mimic of the pygmy-owl’s territorial call were recorded at 66-78 db (Proudfoot and Johnson 2000). Using 3-element Yagi antennas and portable radio-re- ceivers, two researchers tracked a radio-tagged pygmy-owl until obtaining visual contact. One researcher (Rl) visu- ally and electronically monitored the pygmy-owl while an- other researcher (R2) used compass bearings and pacing (Stoddard and Stoddard 1987) to establish a broadcast station at the distance desired for testing (e.g., 500 m). Researchers maintained contact via 2-way radio. If the pygmy-owl moved while R2 was locating the broadcast sta- tion, Rl relayed its new location to R2, and adjustments (repositioning of broadcast station) were made to main- tain the distance desired for testing (e.g., 500 m). A por- table recorder capable of producing 95-105 db at a dis- tance of 1 m from the speaker was used by R2 to broadcast conspecific calls, recorded locally, toward the targeted individual. This equipment met output recom- mendations for raptor broadcast surveys (Fuller and Mosher 1987). While at a station, broadcasting continued for 3 min, during which time any pygmy-owl movement or vocali- zation was recorded. The characteristic call of pygmy-owls is a simple series of interrupted single notes, hence, con- tinued broadcast should not have hampered detectability (Proudfoot and Beasom 1996). To eliminate errors that would result from recording responses from non-targeted individuals, Rl maintained direct observation of test sub- jects during the initial stages of testing, radio-telemetry was used to monitor movement of radio-tagged individ- uals that responded during testing, and R2 located re- sponding individuals that moved toward the broadcast station and verified identification of the test subject with radiotelemetry. Clearly, any reduction in the distance between the broadcast station and the target individual would result in a measurable difference in decibels received at the target’s location. Thus, to test the response distance in a reasonable manner, the distance between broadcast sta- tions should be far enough to result in a significant change in sound reception by the targeted individual. In 1995, testing began at 400 m and increased daily by 100 m increments to 700 m; each individual was tested once daily (Kennedy and Stahlecker 1993). In 1996, sampling was reversed and began at 700 m; if no response was recorded the broadcast station was moved 50 m closer and testing was continued. At each new distance interval a 5-min adjustment period (silence) was observed before broadcasting was resumed. Because we invoked a 5-min adjustment period and visually monitored each individ- ual during testing, we were confident that the response distance recorded was the distance at which the response was elicited. This protocol (5-min of silence followed by 3-min of broadcasting) was repeated until vocal response and movement toward the broadcast station was record- ed. In 1996, we selected the distance (50 m) between broadcast stations based on the time available to conduct tests. Because birds establish territories and maintain and defend areas based on energetic budgets and physical restrictions, confronting conspecifics outside territorial boundaries may be counterproductive. Hence, birds with established territories make response decisions based on assumed location of conspecific and inferred threat (Brown 1969). Therefore, the sample protocol used dur- ing 1996 may simulate natural events and behavior. Pythagorean and Archimedes theorems were used to describe broadcast coverage based on pygmy-owl re- sponse distance information. Theoretical models were used to estimate sampling coverage with regard to effec- tive broadcast radii and spacing of survey points (Fig. 1). For example, with an effective broadcast radius of 550 m, surveyors would essentially sample 94.8% of the rectan- gular area formed from multiplying the distance between survey points (600 m) by the diameter (1100 m) of the broadcast circle. With this sample effort, 34.2% broadcast overlap would occur. If survey points are established 1100 m apart, 78.5% of the described area would be sampled, with 0.0% broadcast overlap (Fig. 1). Resuit’S In 1995, all four pygmy-owls tested at 400 and 500 m responded vocally, moved toward the broad- cast station, and continued to vocalize. At 600 m, three pygmy-owls responded vocally, moved toward the broadcast station, and continued to vocalize; the fourth only responded vocally. Due to time constraints, only one pygmy-owl was tested at 700 m in 1995. It too responded vocally, moved toward the broadcast station, and continued to vocalize. In 1996, two of five pygmy-owls tested at 700 m vocalized, moved toward the broadcast station, and continued to vocalize. A third pygmy-owl responded vocally at 700 m, moved (<100 m) toward the broadcast station and continued to vocalize at 600 m. The fourth pygmy-owl responded vocally at 600 September 2002 Response of Pygmy-Owls 173 A. B. r,(m ni icLAceti S\UATN tr.Ul'Cv.1 Are.i< luullcvtcil I'N Nro.Kk.t»t SiincN iiiinsco ^1 ]'*<* m i'ciwccii >m\c\ j^nrits > ■ ’'^1 2“ o lirivKka^ lAril.ii' \ 1 i'**' Ml •>> ( SSn Ml ) 1 I'N* III ifaiunctcr m iikhus) Figure 1. Schematic rendition of area surveyed along transects with broadcast points established 600 m (A) and 1100 m (B) apart, circles represent area covered with an effective broadcast radius of 550 m applied. m and with vocalization and extensive movement at 550 m. The fifth pygmy-owl responded vocally at 550 m and with vocalization and movement at 250 m. Discussion It is possible that repeated sampling of the same individual on the same evening during 1996 may have influenced our results. However, because we maintained constant observation of the test pygmy- owl during testing and a 5-min period of silence was employed between broadcasts, we submit that the response distance recorded was a reasonable measure of the distance at which the response was elicited (see Methods, above). In addition, because we began testing at 700 m and moved closer to the targeted individual in 50-m increments, any error from repeated sampling would result in conserva- tive response distance estimates. Using the distance at which 100% vocal response was recorded (550 m), the effective coverage of areas formed by establishing survey points from 400-1400 m apart would range from 97.7-61.7%, respectively; broadcast overlap would range from 54.7-0.0%, respectively (Table 1). Our sample size may be considered too small to ascribe absolute response distance parameters. However, our data clearly show that broadcasted conspecific calls may elicit both movement toward the broadcast station and vocal response from pygmy-owls at a distance of 700 m. Consistent with Mays (1996), response distance information obtained from our study strongly suggests redundant sampling may occur along transects with survey points established ^400 m apart. In addition, because several birds tested flew >500 m in response to broadcasted calls, our results question the likelihood that the mean ra- dius of a pygmy-owl’s territory is as small as Wauer et al. (1993) suggested, 297 m. Hence, Wauer et al. (1993) and Mays (1996) may have overestimat- ed the pygmy-owl population size in Texas due to redundant detection of individuals and application of inappropriate territory size to extrapolate pop- ulation estimates. Thus, biased data may have in- advertently altered the U.S. Fish and Wildlife Ser- vice’s perception of a species in concern during the listing process. Our data suggest that transects with survey points spaced from 400-600 m apart would potentially yield a high level of redundant sampling (>30% overlap) . The current survey protocol authorized by 174 Proudfoot et al. VoL. 36, No. 3 Table 1. Estimated percent coverage of rectangular area formed by multiplying observed response diameter (2 X response distance) of Ferruginous Pygmy-Owls in Texas by hypothetical distance (m) between broadcast stations Percent overlap depicts overlap of effective hemispherical response radii. Calculations follow Pythagorean and Ar- chimedes theorems, as simulated in Figure 1 . 1100 m Response Diameter ( 550 m Response Distance) 100% Response‘s 1200 m Response Diameter ( 600 m Response Distance) 89% Response's 1400 m Response Diameter ( 700 m Response Distance) 67% Response's Distance^^ Coverage OVERIAP Coverage OVERI AP Coverage Overlap 400 97.7 54.7 98.1 58.3 100.0 64.1 500 96.4 44.2 96.8 48.6 97.9 55.5 600 94.8 34.2 95.7 39.0 96.9 47.2 700 92.8 24.8 94.6 29.7 95.7 39.1 800 90.3 16.4 92.1 21.8 94.4 31.4 900 87.1 9.3 89.6 14.4 92.7 24.3 1000 83.6 3.3 86.7 8.0 91.4 17.0 1100 78.5 0.0 83.2 2.9 88.5 11.6 1200 72.0 0.0 78.0 0.0 85.9 6.4 1300 66.5 0.0 72.5 0.0 82.7 2.3 1400 61.7 0.0 67.3 0.0 78.7 0.0 ‘ Hypothetical distance between broadcast stations. ^ Response frequency based on analysis of Ferruginous Pygmy-Owl response distances in Texas. the U.S. Fish and Wildlife Service (2000) to deter- mine presence or absence of pygmy-owls in urban and rural areas proposed for development requires a maximum distance of 150 m and 400 m between survey points, respectively. Based on our bndings, this protocol should be an extremely effective means of determining presence of pygmy-owl within areas surveyed. Flowever, due to the excessive over- lap of broadcast radii, using U.S. Fish and Wildlife Service guidelines would undoubtedly not provide accurate census data. In rural areas, the U.S. Fish and Wildlife Service authorized a maximum dis- tance of 500 m between survey points for studies conducted to ascertain the distribution of pygmy- owls in Arizona. A distance of 800 m is allowed if bionic ears or other listing-enhancement devices are used to detect respondents. Due to tree density and background noise (rustling leaves and branches), however, 500 m is maintained as the maximum dis- tance between survey points in riparian areas, re- gardless of utilization of listening aids (U.S. Fish and Wildlife Service 2000). This too should effectively sample areas surveyed for presence or absence of pygmy-owls. However, the level of overlap and, hence, high potential for redundant sampling may render this protocol inaccurate for assessing abun- dance and density. The initial cost of obtaining information regard- ing effective broadcast radius may be substantial, i.e., budgeting personnel and radiotelemetry equipment to conduct a response-distance study. However, the benefits of identifying the effective broadcast radius may transcend initial cost. For ex- ample, if we assume broadcast of conspecific calls will elicit 100% response from pygmy-owls at a dis- tance of 550 m, increasing the distance between broadcast stations from 400-800 m would reduce effective broadcast coverage by 7.4%. However, it would also increase survey efficiency by 100%, and reduce overlap by 38.3%. Reducing overlapping broadcast radii would not only increase area cov- ered, but should also reduce potential redundan- cies in sampling. This type of trade-off may be ad- vantageous for surveying expansive areas with limited personnel resources. Antithetically, utiliz- ing response-distance information, researchers may choose to canvas an area with overlapping ra- dii to maximize detection of species of concern in areas proposed for development. To conclude, this type of research may aid species conservation by providing researchers basic information needed to develop survey protocols that maximize resource allocation with respect to survey intent and effec- tiveness. We suggest that the development of sur- vey protocols should include empirical assessments of sampling effectiveness, both biologically and economically. September 2002 Response oe Pygmy-Owls 175 Acknowledgments We thank B.A. Puente for field assistance; P. Enriquez, R. Honeycutt, R.R. Johnson, R.D. Slack, and J.E. Walter for manuscript review. Funding was provided by Eagle Optics, Exxon Corp., King Ranch Inc., National Fish and Wildlife Foundation, Schott Fiber Optics Inc., Texas Parks and Wildlife Department, and the Texas Wildlife Association. LtrERATURE Cited Aitaire, P.N. and D.F. Landrum. 1975. Summer census of screech owls in Breathitt County. Kentucky Warbler 51:23-29. Brown, J.L. 1969. Territorial behavior and population regulation in birds. Wilson Bull. 81:293-329. DeMaso, S.J., F.S. Guthery, G.S. Spears, and S.M. Rice. 1992. Morning covey calls as an index of Northern Bobwhite density. Wildl. Soc. Bull 20:94—101. Emlen, J.T. 1977. Estimating breeding season bird den- sities from transect counts. Auk 94:455-468. Fuller, M.R. and J.A. Mosher. 1987. Raptor survey tech- niques. Pages 37-65 in B.G. Pendleton, B.A. Millsap, K.W. Cline, and D.M. Bird [Eds.]. Raptor manage- ment techniques manual. National Wildlife Federa- tion, Washington, DC FI.S.A. Gilman, M.F. 1909. Some owls along the Gila river in Arizona. Condor 11:145-152. Jc:)HNSON, R.R., B.T. Brown, I..T Haight, and J.M. Sim- son. 1981. Playback recordings as a special avian cen- sus technique. Stud. Avian Biol. 6:68-71. Kennedy, P.L. and D.W. Stahlecker. 1993. Responsive- ness of nesting Northern Goshawks to taped broad- cast of 3 conspecific calls. J. Wildl Manage. 57:249- 257. Mays, J.L. 1996. Population size and distribution of Cac- tus Ferruginous Pygmy-Owl in Brooks and Kenedy Counties, Texas. M.S. thesis. Texas A&M University, Kingsville, TX U.S.A. McLeod, M.A. and D.E. Anderson. 1998. Red-shoul- dered Hawk broadcast surveys: factors affecting detec- tion of responses and population trends. J. Wildl Manage. 62:1385—1397. McNicholl, M.K. 1978. A census of screech owls {Otus asio) using tape-recorded cAh. Jack-Pine Warbler 52:99- 101 . Millsap, B.A. and R.R. Johnson. 1988. Ferruginous Pyg- my-Owl. Pages 137-139 in R.L. Glinski, B.G. Pendle- ton, M.B. Moss, M.N. LaFranc, Jr., B.A. Millsap, and S.W. Hoffman [Eds.]. Proceedings of the Southwest Raptor Management Symposium and Workshop. Na- tional Wildlife Federation, Washington, DC U.S.A Oberhoi ser, H.C. 1974. The bird life of Texas. Univ of Texas Press, Austin, TX U.S.A. Proudeoot, G.A. and S.L. Beasom. 1996. Respon.siveness of Cactus Ferruginous Pygmy-Owls to broadcasted conspecific calls. Wildl Soc. Bull 24:294—297. AND R.R. Johnson. 2000. Ferruginous Pygmy-Owl (Glaucidium brasilianum) . In A. Poole and F. Gill [Eds.]. The birds of North America, No. 498. The Birds of North America, Inc. Philadelphia, PA U.S.A. Smith, D.G., A. Devine, and D. Walsh. 1987. Censusmg screech-owls in southern Connecticut. Pages 255—267 mR.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Ham- re [Eds.], Biology and con.servation of northern forest owls. USDAFor, Serv. Gen. Tech. Rep. RM-142. Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO U.S.A. Springer, D.G. 1969. Foot surveys versus owl calling sur- veys; a comparative study of two Great Horned Owl census techniques. Inland Bird Banding Neivs 50:83-92. Stoddard, C.H. and G.M. Stoddard. 1987. Essentials of forestry practice, 4th Ed. John Wiley and Sons, Inc , New York, NY U.S.A. Stahlecker, D.W. and JJ- Rawinski. 1990. First records for the Boreal Owl in New Mexico. Condor 92:517- 519. U.S. Fish and Wildlife Service. 1983. Instructions for conducting breeding bird survey routes. Migratory non-game bird studies, Patuxent Wildl. Res. Center, Laurel, MD U.S.A. . 1997. Endangered and threatened wildlife and plants; Determination of endangered status for the Cactus Ferruginous Pygmy-Owl in Arizona. Fed. Reg 62:10730-10747. . 2000. Notice of availability; Guidance for private landowners concerning the Cactus Ferruginous Pyg- my-Owl; and the Cactus Ferruginous Pygmy-Owl sur- vey protocol. Fed. Reg. 65:14999-15000. Wauer, R.H., P.C. Palmer, and A. Windham. 1993. The Ferruginous Pygmy-Owl. Am. Birds 47:1071-1076. Received 21 May 2001; accepted 17 May 2002 Former Associate Editor: Cole Crocker-Bedford / Raptor Res. 36(3):176-182 © 2002 The Raptor Research Foundation, Tnc. POST-FLEDGING SURVIVAL AND DISPERSAL OF PEREGRINE FALCONS DURING A RESTORATION PROJECT Larkin A. Powell, ^ Dan J. Cai.vert, and Irene M. Barry Environmental Science Department, University of Dubuque, 2000 University Avenue, Dubuque, lA 52001 US. A. Lowell Washburn Iowa Department of Natural Resources, 1203 N. Shore Drive, Clear Lake, lA 50428 US. A. Abstract. — ^We monitored 38 juvenile Peregrine Falcons {Falco peregrinus) up to 3 mo immediately after their release from a hack box during 1999-2000. The restoration site was a cliff near Eagle Point Park in Dubuque, Iowa. Falcons were released in a staggered manner from midjune until late July each summer. Older falcons remained at the site longer than at previous urban releases and interacted with the younger falcons. The four mortalities (11%) confirmed during the observation periods were dis- covered and reported by citizens near the release site. We used radiotelemetry, observations of color- marked birds at the hack site, and recovered mortalities to estimate weekly survival rates and dispersal patterns. We estimated weekly survival rate to be 0.988 (SE = 0.01), and our weekly re.sighting rate was high: 0.885 (SE = 0.03). Juveniles were observed for an average of 4.3 wk in 1999 (SD = 2.5), but only 3.4 wk in 2000 (SD = 2.3). Accordingly, weekly fidelity rates were year-specific: 0.903 (SE = 0.03) in 1999 and 0.795 (SE = 0.05) in 2000. No mortalities were attributed to Great-horned Owl {Bubo vir^- nianus) predation, but substantial numbers of owls were seen in summer 2000. The presence of owls in 2000 may have contributed to the difference in fidelity rates and dispersal patterns between years. Key Words: Peregrine Falcon', Falco peregrinxis; survival; dispersal; mark-recapture model, population restoration. Sobre vivencia de volantones y dispersion de halcones peregrinos durante un proyecto de restauracion Resumen. — Monitoreamos 38 halcones peregrinos {Falco peregrinus) juveniles hasta 3 meses inmediata- mente despues de su liberacion desde una “caja de suelta” durante 1999-2000. El sitio de restauracion era un risco cerca la parque Punto del Aguila en Dubuque, Iowa. Los halcones fueron liberados en forma escalonada desde mediados de junio hasta finales de julio de cada verano. Los halcones mas adultos perraanecieron por mas tiempo en los sitios urbanos en los cuales interactuaron con los halcones mas jovenes. Las cuatro muertes (11%) confirmadas durante los periodos de observacion fueron des- cubiertas y reportadas por ciudadanos cerca a los sitios de liberacion. Utilizamos la telemetria y las observaciones de aves marcadas con colores en los sitios de liberacion. La recoleccion de animales muertos fue utilizada para estimar la tasa de sobrevivencia semanal y los patrones de dispersion. Esti- mamos la tasa de sobrevivencia semanal en 0.988 (SE = 0.01), y una tasa de avistamientos semanal alta: 0.885 (SE = 0.03). Los juveniles fueron observados en un promedio de 4.3 por semana en 1999 (SD = 2.5), pero solo fue de 3.4 en el 2000 (SD = 2.3). En concordancia, las Lasas de fidelidad semanal fueron especificas para cada ano; 0.903 (SE = 0.03) en 1999 y 0.795 (SE = 0.05) en el 2000. No hubo mortalidades atribuibles a la depredacion por parte de Bubo virginianus. Sin embargo, un numero im- portante de buhos fue observado en el verano del 2000, lo que pudo haber contribuido a las diferencias en las tasa de fidelidad y en los patrones de di.spersion entre ahos. [Traduccion de Cesar Marquez] Peregrine Falcons {Falco peregrinus) once nested on ledges of bluffs along Iowa rivers, but they were extirpated in the 1950s and 1960s. Recovery efforts 1 Current address: School of Natural Resource Sciences, 202 NRH, University of Nebraska, Lincoln, NE 68583- 0819 U.S.A.; e-mail address: lpowell3@unl.edu in urban areas have been successful, by using tops of tall city buildings as hack sites to release captive- hatched juveniles. Because of efforts in Iowa and surrounding states, the Midwestern population had grown to 67 territorial pairs by 1997, with 747 captive-produced juveniles released (Tordoff and Redig 1997) . As of 2002, Peregrine Falcons are still 176 September 2002 Peregrine Post-fledging Survivai. 177 listed as an endangered species in Iowa. In 1998, the Iowa Department of Natural Resources (DNR) began a program of cliff-habitat releases. During the summer of 1999, the city of Dubuque, lA be- came the site of Iowa’s second cliff release. Juveniles are hacked in the absence of their par- ents. Therefore, humans feed the juveniles with farm-raised quail carcasses, and the hatchlings in- teract with their siblings to learn flying and hunt- ing skills, much as they would in the presence of their parents (Sherrod et al. 1981). Great-horned Owl {Bubo virginianus) predation has been a key factor in the success of previous releases (Barclay and Cade 1983, Redig and Tordoff 1988) . Our pro- ject was developed to monitor the survival and dis- persal of juveniles from the hack site area in the context of (1) a relatively large cliff release and (2) concerns of owl predation. Natal dispersal is the movement from the hatch site to a breeding territory (Greenwood and Har- vey 1982), and previous studies have reported on Peregrine Falcon natal dispersal (e.g., Tordoff and Redig 1997, Restani and Mattox 2000). Although natal dispersal is often used as an indicator of re- cruitment success, the period immediately follow- ing fledging may be the most critical to the survival of juvenile Peregrine Falcons (Barclay and Cade 1983). In this paper, we refer to this period as the “post-fledging period,” and we use the dispersal of the juveniles away from the hack site as the func- tional end of this period. Very little information has been published on the survival and movements of juvenile Peregrine Falcons during the post-fledging period (but see Perez and Zwank [1995] for Aplomado Falcons [Falco femoralis ] ) . Our goal was to determine the initial viability of the juvenile falcons released by the Iowa DNR at the cliff hack site. To do this, we monitored movements, determined habitat use, and estimated survival during the post-fledging pe- riod, prior to migration. Methods We conducted this study during June-September of 1999 and 2000 in Dubuque County, Iowa (42°30'N, 90°38'W). We placed two hack boxes at the top of a 50- m, east-facing cliff, on the Mississippi River, just below Lock and Dam 11 (Fig. 1). Birds were released in a stag- gered manner beginning on 22 June 1999 and 20 June 2000 (Fig. 2). Prior to release, we banded each juvenile with a unique color- and alpha-numerically-coded leg band, in addition to the National Bird Banding lab’s (USGS-BRD) anod- ized band. We also color-marked each juvenile on either the wing or tail with non-toxic paint. For individuals marked on a single wing, we also marked the opposite side of the head, behind the eye, to allow observers to determine identity from any angle. We monitored color-marked birds at the hack site from an observation point below the cliff, using a spotting scope and binoculars. Observations were taken daily, usu- ally at 0600-0830 H, 1100-1300 H, and 1800-2030 H During 1999, we radio-marked five individuals with leg- mounted transmitters. Because the falcons were able to remove the leg-mounted transmitters, we switched to backpack harnesses on four individuals during 2000. We determined the location of radio-marked birds by trian- gulating with at least two bearings, once each day follow- ing release; bearings were taken from six fixed points surrounding the cliff site. We used Magellan GPS receiv- ers to determine the coordinates of the fixed points, and we used LOCATE II software to estimate the actual co- ordinates of each bird from the bearing data (Nams 1990). We mapped the position of each bird using ArcView GIS software, version 3.2, and determined home range using the Jennrich-Turner home range algorithm (Jennrich and Turner 1969) within ArcView as an exten- sion (Hooge and Eichenlaub 1997). Compared to other home range estimators, the Jennrich-Turner method is especially useful for determining confidence intervals of home range size and deriving the axes of groups of lo- cation coordinates (Hooge and Eichenlaub 1997). We calculated the proportion of fatalities in our sample based on documented deaths. We calculated 95% confi- dence intervals (Cl) for each binomial sample propor- tion (Burleson 1980). To facilitate comparisons with oth- er studies, we also calculated an adjusted proportion of fatalities by considering birds that disappeared from the hack site within the first two weeks after release as dead (three of our confirmed mortalities happened in the first week and one happened in the third week). The latter method incorporates many biases and assumptions, and we suggest is a “worst case” scenario. Just as we do not know wbat happened to birds that disappeared during the first 2 wk, surveys of most wildlife populations are unable to detect all animals in the in- tended population. To estimate the probability of surviv- ing a given time interval robustly, it is necessary to use methods which adjust for incomplete detectability (Thompson et al. 1998). Therefore, we summarized our resighting data into weekly discrete time intervals for analysis in a Cormackjolly-Seber mark-recapture design (Pollock et al. 1990). This method allows the estimation of weekly survival rates (the probability of surviving one week) , as well as other parameters. We estimated demographic parameters using recovery data from dead birds and resighting data from live birds in the same estimating model (Burnham et al. 1987) in program MARK (White and Burnham 1999). In addition to the usual survival and resighting (the probability of being detected during a week given that the animal is alive) parameters, the incorporation of known deaths to the data set allowed the estimation of a fidelity parameter (4i, the probability of remaining at the site during a given week; Burnham et al. 1987). We considered several po- tential models that varied by whether parameters were year-specific or pooled across the 2 yr (Table 1). Because Figure 1. Ranges and locations of radio-marked, juvenile peregrine during 1999—2000 (A), immediately following release from a hack site (A) at Eagle Point Park in Dubuque, lA along the Mississippi River (B). Ellipsoids indicate 95% of home range as determined by the Jennrich-Turner method (Jennrich and Turner 1969); small ellipsoid is for 1999 and large ellipsoid is for 2000. September 2002 Peregrine Post-fledging Survival 179 ■o <0 (.)} 2.79 0.0690 5 IS(g) p(.) r(.) 4^(.)} 3.16 0.0573 5 |S(.) p(g) r(.) 4^(.)} 3.33 0.0528 5 |S(g) p(g) r(g) 4^(g)} 6.31 0.0117 8 ® AIC Weight is the weight of evidence in favor of the given model being from the set of models considered. AIC Weight is a func- tion of the model’s AAIC^ value, compared to the other models’ AAICc values (Burnham and Anderson 1998). In our data set, the best model is twice as likely (0.2*786 compared to 0.1464) as the second-best model to be the best model. immediately around the hack site to dissuade mammal scavengers, and several raccoons {Procyon lotor) and a red fox (Vulpes vulpes) were seen near the hack site. The death in 2000 resulted from an electrocution on a power pole; several falcons were seen using the utility pole as a roost prior to the mortality. No detected fatality appeared to be the result of Great-horned Owl predation. The mean distance of the four deaths from the hack site was 676 m (SD = 411). Weekly survival (S = 0.988, SE = 0.01) did not differ between years, and our weekly resighting probability (p) was also constant between years (p = 0.885, SE = 0.03; Table 1). Extrapolating the weekly survival to the entire post-fledging period resulted in a 10-wk survival rate of S = 0.886 (SE = 0.07, or a 0.114 mortality rate estimate for the same 10-wk period); assuming constant survival for the first year would result in an annual survival es- timate of S = 0.534 (SE = 0.84). 180 POW'ELL ET AE. VoL. 36, No. 3 Dispersal. We observed first-year juveniles at our hack site from 22 June-12 September in 1999 and from 20 June-9 August 2000 (Fig. 2). No juveniles from 1999 were observed in 2000, and no juveniles from either year were observed at the site in sum- mer 2001. Individual juvenile falcons were observed for a mean of 4.3 wk (SD = 2.5) during 1999, and for a mean of 3.4 wk (SD = 2-3) during 2000 (F’l 3 g = 2.82, P — 0.10). Weekly fidelity (v|t) the probability of not dispersing from the hack site during the week) was lower in 2000 (1999: 4^ = 0.903, SE = 0.03; 2000: vl; = 0.795, SE = 0.05; Table 1). Habitat Use. We observed color-marked birds most often at the hack boxes. However, the juve- niles also used the cliff face for roosting, feeding, and social interactions. In addition, we observed juveniles in trees surrounding the hack site. In 1999, 23 of the 28 (82%) “non-hack site” obser- vations were from the cliff face; 5 of the 28 (18%) were from trees. In 2000, only 31 of 72 (43%) “non-hack site” observations were from the cliff face; 41 of the 72 (57%) were from the trees (x^ = 5.56, df - 1, P = 0.018). In 1999, we obtained 17 sets of useable bearings from radio-marked birds before the leg-mounted radios fell off the birds. The birds were observed picking at the leather/ cotton thread attachments, and were soon able to dislodge the transmitters; otherwise, all behaviors of radio-marked birds were normal. In 2000, we obtained 40 sets of useable bearings; apparent signal bounce from the cliff walls prevented program LOCATE II from deter- mining a precise location estimate for other sets of bearings. Birds remained closer to the cliff and hack site during 1999 than in 2000. The mean dis- tance of radio-marked birds from the hack site was 268 m (SD = 296.2) during 1999; in 2000, the mean distance was 619 m (SD = 871, t = 2.26, df = 53, P = 0.03; Eig. 1). In 1999, the minimum distance from the hack site was 72 m and the max- imum was 1342 m; in 2000, the minimum was 52 m and the maximum was 5329 m. The number of useful sets of bearings per bird ranged from 1-8 in 1999, and from 4-22 in 2000; the backpack har- nesses in 2000 provided more useful data, al- though one fell off prematurely. Movements of young peregrines were more of- ten in an east-to-west direction (“inland” from the river), than in a north-to-south direction (along the river) . The home range ellipsoid, representing 95% of their daily use, for birds in 1999 was 75 ha. and measured 1861 m south west-to-northeast and 512 m northwest-to-southeast; in 2000 the home range ellipsoid was 682 ha, and measured 4839 m east-to-west and 1795 m north-to-south. In both years, the ellipsoid covered Eagle Point Park, Mis- sissippi River, islands on the river, and some urban area. At least 50% of the area was covered by the forested Park (Fig. 1). Discussion We did not design this study to measure the ef- fects of Great-horned Owls on juvenile Peregrine Falcons. However, the increased presence of owls at the hack site in 2000 suggests rationale for the observed changes in peregrine behavior. In 2000, when more owls were seen, peregrine juveniles had lower site fidelity, shorter mean observation peri- ods, increased daily distance from the hack site, and greater use of more secluded perch sites (trees). However, survival did not seem to be af- fected by the presence of the owls. Availability of quail at the hack site may have attracted the owls, while also satisfying the owls’ dietary needs (thus, reducing predation pressure on the falcons). At the least, our study provides evidence that pere- grine restoration projects can be carried out suc- cessfully in the presence of Great-horned Owls (but see Craig et al. 1988, Redig and Tordoff 1988). The Iowa Department of Natural Resources con- sidered this release to be successful for several rea- sons, including high post-fledging site fidelity and survival. Juveniles from previous urban releases in Iowa have left the hack site much earlier (ca. 2 wk) than the juveniles from Dubuque’s natural cliff site (P. Schlarbaum pers. comm.). The longer time spent at the hack site during the post-fledging sea- son could provide for higher survival to the migra- tory period. Juveniles remained at hack sites in Canada for a mean of 22.9-27.7 d (Fyfe 1988) and from 4—7 wk in Sweden (Lindberg 1988), com- pared to our observations of 4.3 wk (30 d) in 1999 and 3.4 wk (24 d) in 2000. Fyfe (1988) also re- ported that birds remained longer at the site of multiple releases, similar to ours. Radio-marked juveniles in this study had a much more limited range than juveniles or adults in oth- er studies. For comparison, Enderson and Kirven (1983) reported long (^1 km) daily movements for an adult male. Jenkins and Benn (1998) re- ported mean flights of 10.3-21.9 km for adult males and females, with a mean home range of 123 September 2002 Peregrine Post-fledging Survival 181 km^. Perez and Zwank (1995) found dispersal flights of 2-16 km for juvenile Aplomado Falcons in Texas. The farthest distance we recorded a fal- con from the hack site was just over 5 km, and the combined home range for our group of falcons in 2000 was just 472 ha. The continued presence of food at the hack site, in addition to forest habitat concentrated near the Mississippi River probably contributed to this observation. Approximately 90% of all juveniles survived the 10-wk post-fledging period, and the sources of mor- tality were similar to those reported by Barclay and Cade (1983). Our observed mortality of 10.5% was very similar to the 10-wk mortality rate of 11.4% estimated using the mark-recapture model. The survival of these juveniles was high compared to other estimates. Burnham et al. (1988) estimated that 81% of hacked young survived three weeks in the Rocky Mountain region during 1976-85; our survival over 3 wk would be 96.4%. Barclay and Cade (1983) used estimates from other raptor spe- cies to arrive at an approximation of 75% survival during the pre-dispersal period — the same as our worst-case scenario estimate. Tordoff and Redig (1997) used resightings of Peregrine Falcons to es- timate a minimum first-year survival estimate of 23%, although many survivors were probably not resighted. Our extrapolated first-year survival rate of 53% could potentially be lowered by migratory mortalities. However, the period we monitored may be the most hazardous for juveniles without parental protection (Barclay and Cade 1983); all of our documented fatalities occurred during the first 1-3 wk following fledging. Thus, annual sur- vival could actually be higher than 53% for the birds we monitored. For comparison, Tordoff and Redig (1997) reported a survival rate of 86% for adults in the Midwest; they also determined that hacked juveniles survived at better rates than wild juveniles in the Midwest. Juvenile survival rates are critical, because a low proportion of available individuals are recruited into the breeding population (Tordoff and Redig 1997, Restani and Mattox 2000). With 38 juveniles released in one location and high survival rates, the cliffs near Dubuque, lA on the Mississippi River have high potential to host a breeding pair in the near future. Ac:kn o weed gments We are grateful to the Iowa Department of Natural Re- sources and the Iowa Falconers Association for providing the Peregrine Falcon release for this study. The city of Dubuque and Eagle Point Park provided the location for the release. Several members of the Dubuque Audubon Society worked as volunteer feeders and monitors during 1999. J. Monat, J. Robertson, and D. Reding provided field assistance during 2000. This undergraduate re- search was sponsored by a grant from Region 3 of the U.S. Fish and Wildlife Service, as well as Student Re- search Grants, a Faculty/Student Research Grant from the McElroy Trust and Maytag Foundation of the Iowa College Foundation, and the School of Natural Resource Sciences at the University of Nebraska— Lincoln. Literature Cited Barclay, J.H., and TJ. Cade. 1983. Restoration of the Peregrine Falcon in the eastern United States. Pages 3-40 in S. Temple [Ed.], Bird conservation. Vol 1 Univ. of Wisconsin Press, Madison, WI U.S.A. Burleson, D.R. 1980. Elementary statistics. Winthrop Publishers, Cambridge, MA U.S.A. Burnham, K.P. and D.R. Anderson. 1998. Model selec- tion and inference: a practical information-theoretic approach. Springer-Verlag, New York, NYU.S.A. , D.R. Anderson, G.C. White, C. Brownie, and K.H. Pollock. 1987. Design and analysis methods for fish survival experiments based on release-recapture Am. Fish. Soc. Monogr. No. 5. Burnham, W.A., W. Heinrich, C. Sandeort, E. Levine, D. O’Brien, and D. Konkel. 1988. Recovery effort for the Peregrine Falcon in the Rocky Mountains. Pages 565-574 in T.J. Cade, J.H. Enderson, C.G. Thelander, and C.M. White [Eds.], Peregrine Falcon populations, their management and recovery. The Peregrine Fund, Inc., Boise, ID U.S.A. Craig, G.R., D.D. Berger, and J.H. Enderson. 1988. Per- egrine management in Colorado. Pages 575—586 in T.J. Cade, J.H. Enderson, C.G. Thelander, and C M White [Eds.], Peregrine Falcon populations: their management and recovery. The Peregrine Fund, Inc., Boise, ID U.S.A. Enderson, J.H. and M.N. Kirven. 1983. Elights of nesting Peregrine Ealcons recorded by telemetry. Raptor Res 17:33-37. Fyfe, R.W. 1988. The Canadian Peregrine Falcon recov- ery program, 1967-1985. Pages 599-610 in T.J. Cade, J.H. Enderson, C.G. Thelander, and C.M. While [Eds.], Peregrine Falcon populations: their manage- ment and recovery. The Peregrine Fund, Inc., Boise, ID USA. Greenwood, P.J. and P.H. Harvey. 1982. The natal and breeding dispersal of birds. Ann. Rev. Ecol. Syst. 13:1- 21 . Hooge, P.N. and B. Eichenlaub. 1997. Animal move- ment extension to Arc View (Ver. 1.1). Alaska Biolog- ical Science Center, U.S. Geological Survey, Anchor- age, AK U.S.A. Jenkins, A.R. and G.A. Benn. 1998. Home range size and 182 Powell et al. VoL. 36, No. 3 habitat requirements of Peregrine Falcons on the Cape Peninsula, South Africa./. Raptor Res. 32:90-97. Jennrich, R.I, AND F.B, Turner. 1969. Measurement of non-circular home range. /. Theor. Biol. 22:227-237. Lindberg, P. 1988. Reintroducing the Peregrine Falcon in Sweden. Pages 619-628 wT.J. Cade.J.H. Enderson, C.G. Thelander, and C.M. White [Eds.], Peregrine Falcon populations: their management and recovery. The Peregrine Fund, Inc., Boise, ID, U.S.A. Nams, V.O. 1990. Locate II user’s guide. Pacer software: Truro, Nova Scotia, Canada. Perez, C.J. and PJ Zwank. 1995. Dispersal and habitat selection of released Aplomado Falcons./. Raptor Res. 29:64. Pollock, K.H., J.D. Nichols, C. Brownie, and J.E. Hines. 1990. Statistical inference for capture-recap- ture experiments. Wildl. Monogr. 107. Redig, P.T. and H.B. Tordoff. 1988. Peregrine Falcon reintroduction in the upper Mississippi Valley and western Great Lakes region. Pages 559-564 in T.J. Cade, J.H. Enderson, C.G. Thelander, and C.M. White [Eds.], Peregrine Falcon populations: their manage- ment and recovery. The Peregrine Fund, Inc., Boise, ID U.S.A. Restani, M. and W.G. Mattox. 2000. Natal dispersal of Peregrine Falcons in Greenland. Auk 117:500-504. Sherrod, S.K., W.R. Heinrich, W.A. Burnham, J.H. Car- clay, and T.J. Cade. 1981. Hacking: a method for re- leasing Peregrine Falcons and other birds of prey. The Peregrine Fund, Inc., Fort Collins, CO U.S.A. Thompson, W.L., G.C. White, and C. Gowan. 1998. Mon- itoring vertebrate populations. Academic Press, San Diego, CA U.S.A. Tordoff, H.B. and P.T. Redig. 1997. Midwest Peregrine Falcon demography, 1982-1995./ Raptor Res. 31:339- 346. Weir, B.S. 1990. Genetic data analysis. Sinauer Assoc., Inc., Sunderland, MA U.S.A. White, G.C. and K.P. Burnham. 1999. Program MARK: survival estimation from populations of marked ani- mals. Bird Study 46 Supplement: 120-1 38. Received 13 November 2001; accepted 19 May 2002 /, Raptor Res. 36(3):183— 187 © 2002 The Raptor Research Foundation, Inc. MORPHOLOGY, GENETICS AND THE VALUE OF VOUCHER SPECIMENS: AN EXAMPLE WITH VULTURES Carole S. Griffiths' Biology Department, Long Island University, 1 University Plaza, Brooklyn, NY 11201, and Department of Ornithology, American Museum of Natural History, New York, NY 10024 US. A. John M. Bates Bird Department, Field Museum of Natural History, Chicago, JL 60604 U.S.A. Abstract. — Similarity of two of the cathartid vultures, the Greater and Lesser Yellow-headed vultures (Cathartes melambrotus and C. burrovianus) has caused field-identification problems. The primary means of distinguishing those vultures are the different flight profiles and general habitat preferences. As part of a larger study of cathartid phylogeny, we sequenced cytochrome b for six specimens of the two species. Sequences segregate into two groups, with two of the four Lesser Yellow-headed Vulture specimens clustering with the Greater Yellow-headed specimens. This incongruence led us to reexamine the two apparently misidentified specimens. The first bird, a specimen from the Sedgwick County Zoo, Kansas, had been acquired in 1960 and identified as a yellow-headed vulture. The name on the label of this specimen was not changed after melambrotus was established as a separate species in 1964. The second specimen, from Amapa, Brazil, had been identified based on observations of habitat and flight behavior. Because this voucher specimen was available for study, we were able to reexamine the specimen and corroborate the molecular identification as a Greater Yellow-headed Vulture. Without these voucher specimens, we would have misinterpreted the results from the molecular data. This is a reaffirmation of the importance of voucher specimens for accurate scientific work. Key Words: yellow-headed vultures', Cathartes burr ovianus; Cathartes melambrotus; voucher specimens', cy- tochrome b; genetics. Morfologia, genetica y el valor de los especimenes de gaveta; Un cjemplo con los buitres del genero Cathartes Resumen. — ^La similaridad entre dos buitres del genero Cathartes: Cathartes melambrotus y C. burrovianus ba causado problemas de identificacion en campo. La diferencia principal para distinguir estas especies son el perfil de vuelo y sus preferencias de habitat. Como parte de un estudio de filogenia de los Catharlidae, hicimos una secuencia del citograma b para seis especimenes de dos especies. Las secuencias fueron separadas en dos grupos, con dos de los cuatro especimenes de Cathartes burrovianus agrupados con los especimenes de Cathartes melambrotus. Esta incongruencia permitio re-examinar a dos especimenes incor- rectamente identificados. El primero, un especimen del zoologico del Condado de Sedgwick, Kansas, fue adquirido en 1960 y fue identificado como Cathartes burrovianus. El nombre en el rotulo de este especimen no fue cambiado despues de que melambrotus fue establecido como especie aparte en 1964. El segundo especimen, procedente de Amapa, Brasil, habia sido identificado con base en observaciones de habitat y comportamiento de vuelo. Debido a que este especimen estaba disponible para estudio, pudimos re- examinar el ave y corroborar la identificacion molecular como Catarthes melambrotus. Sin estos especimenes de gaveta, hubieramos mal interpretado los re.sultados de los datos moleculares. Esta es un reafirmacion de la importancia de los especimenes de gaveta para el trabajo cientifico. [Traduccion de Cesar Marquez] Morphologically similar avian species can be dif- ficult to distinguish in the field. Typically, species identical in appearance are identified by where ^ E-mail address: cgriff@liu.edu they are located (habitat), by their song or calls (e.g., Empidonax flycatchers), and possibly other characters such as behavior (Zimmer et al. 2001). Here, we present genetic data and provide an ex- ample of how voucher specimens were vital in the interpretation of results and in the identification 183 184 Griffiths and Bates VoL. 36, No. 3 Table 1. Wetmore’s (1964) measurements (mm) of Yellow-headed Vultures. Greater Yellow-headed Lesser Yellow-headed Vulture Vulture C. B . BURROVIANUS C. B . URUBITINGA C. MEIJiMBROTUS Male Female Mai.e Female Male Female Tail length Central rectrix width 195-225 42-49 193-230 43-49 205-238 43-50 204-236 43-51 252-275 59-70 272-285 60-67 of species of New World Vultures ( Cathartes) . This genus currently comprises three species, the Tur- key Vulture {Cathartes aura) and the Greater and Lesser Yellow-headed vultures ( C. melambrotus and C. burrovianus, respectively). The two yellow-headed vultures are so similar that they were only recognized as separate species when Wetmore (1964) revised the genus. Wetmore designated the Greater Yellow-headed Vulture as a separate species based on differences in overall plumage color and in size. The distinctive mea- surements are length of the tail and the width of the central rectrices (Wetmore 1964; Table 1). The Lesser Yellowdieaded Vulture was subdivided into two subspecies: C. burrovianus burrovianus, the smaller, northern form occurring from Mexico to Venezuela and the slightly larger C. burrovianus urubitinga, which occurs from Venezuela and Co- lombia south to northern Aigentina and Uruguay. The similarity of the Greater and Lesser Yellow- headed vultures has caused problems in identifying birds in the field (Blake 1977, de Schauensee and Phelps 1978); the slight differences in size and head color are not useful in most field circum- stances. The primary means of distinguishing these two species are different flight profiles and general habitat preferences. Hilty and Brown (1986) also emphasize differences in general coloration (the Greater Yellow-headed Vulture is darker overall with less lighter coloration on the flight feathers) and in the color of primary quills (white in the lesser yellow-headed, dark in the greater yellow- headed) that can be seen from above in a flying bird. Because these plumage features are difficult to use in many field situations, the two speeies are likely to be most frequently identified by location and method of hunting. The Lesser Yellow-headed Vulture is considered to be a bird of marshes, flat grass, and open wetland habitats (de Schauensee 1970, Houston 1994, Hilty and Brown 1986), rarely found in forests (del Hoyo et al. 1994). In contrast, the Greater Yellow-headed Vulture occurs in ma- ture lowland forests and along forest edges (de Schauensee and Phelps 1978, Houston 1994, Siek 1993), rarely wandering over grassland (Hilty and Brown 1986). It hunts by flying over the forest can- opy, using a sense of smell to locate carrion (del Hoyo et al. 1994, Houston 1994). Possibly because of its habitat preference, it is considered to soar at greater heights, with a steadier flight pattern, and with wings flatter than the lesser yellow-headed (Hilty and Brown 1986, Sick 1993). The potential for some overlap to occur at forest edges with flooded grassland only increases the difficulty of evaluating some sight records (see Ridgely and Greenfield 2000). As part of a larger study of cathartid phylogeny, tissue specimens of Greater and Lesser Yellow- headed vultures were obtained from museums and from a zoo (Table 2), and a mitochondrial gene, cytochrome b, was amplified and sequenced for six individuals. In this paper, we report on sequence divergence between the two species. In addition, we discuss the misidentification of two specimens, the useful- ness of various methods of identifying these spe- cies, and, reiterate the importance of voucher spec- imens for accurate faunistic and taxonomic studies. Methods Taxon Sampling. Four specimens originally identified as C. burrovianus, and two specimens identified as C. me- lanibrolus v/erc analyzed (Table 2). DNA Extraction, Amplification, and Sequencing. DNA was extracted from frozen tissue samples using DNAzol (Molecular Research), according to manufacturers’ in- structions and then subjected to PCR reactions. Primers (Table 3) were used to amplify and sequence overlapping regions of both strands of the mitochondrial cytochrome b gene. PCR reactions were run in a PTC-200 Peltier Thermal Cycler machine. Double-stranded DNA was generated in 30 |xl solutions run at 40 cycles: 20 sec at 94°C, 15 sec at 55°C, and 1 min at 72°C. The double-stranded DNA tem- plate was purified using Geneclean 11 (Bio 101 Inc., Vista, September 2002 Genetics of Cathartes Vultures 185 Table 2. Voucher numbers and locations of the birds used in this study. Species Voucher No. Location Cathartes melambrotus LSUMNS^ B9005 Pando Department, Bolivia LSUMNS B7175 Loreto Department, Peru Cathartes burrovianus KUNHM** 89344 Yucatan, Mexico KUNHM 1872 Yucatan, Mexico MPECV CH-268 Amapa, Brazil SCZd 4550 Sedgwick County Zoo Louisiana State University Museum of Natural Sciences. ’’ University of Kansas Natural History Museum. Museu Paraen.se Emilio Goeldi. Sedgwick County Zoo. CA) and resuspended with 18 |xl of ultra pure water. Two |jl1 were used as template for cycle sequencing using a Prism® Ready Reaction DyeDeoxy® Terminator Cycle Sequencing Kit. Protocol for the 6 pi reactions was: pre- heating for 1 min at 95°C, then 35 cycles at 95°C for 15 sec, 50°C for 15 sec, and 60°C for 4 min. The product was precipitated using 74 pi of an ethanol/MgCl 2 mix- ture, cleaned with 95% ethanol and resuspended in 2.2 pi of a 6 to 1 solution of formamide-EDTA. Two pi of the sequenced product were loaded into a 6% acryl- amide gel and analyzed in an ABI Model 377 DNA se- quencer. parisons of each of these species to the Turkey Vul- ture (C. aura). The incongruence of these results led us to re- examine the two apparently misidentified Lesser Yellow-headed Vulture specimens. A tail measure- ment (MPEG CH-268, length 267 mm) or a mea- surement of the central retrix (SCZ 4550, width 62 mm) was taken. These measurements clearly fall within the range of the Greater Yellow-headed Vul- ture (Table 1). Results The cytochrome b sequences of these species have been deposited in Genbank (Accession num- bers AF494339— AF494342) . Sequences of the six specimens segregate into two groups (Table 4), with two of the four L.esser Yellow-headed Vultures (SCZ 4550 and MPEG CH-268) clustering with the Greater Yellow-headed specimens. Within each of these two groups, sequences diverge by 0.09% (one character), between the two groups divergence is 2.7% (31 characters). This level of divergence is similar to the number of sites that differ in com- Table 3. The sequences of primers used to amplify over- lapping regions of both strands of cytochrome b. Name Location"* * Sequence (5' to 3') L14851b 14851 H15149" 15298 L15162^ 15311 H15780 15780 L15636 15636 H16057 16057 CCTACTTAGGATCATTCGCCCT GCCCCTCAGAATGATATTTGTCCTCA CTACCATGAGGACAAATATC TAGGAATAGGATTAGTACGGAGGCAG CTAACAACCCTAGCCCTATTCTCACC CTCTGGTAACAAGACCAATG "* Based on chicken sequence (Desjardins and Morais 1990). >*Groth (1998). * Helm-Bychoswki and Cracraft (1993). Discussion The reason for the apparent misidentihcation of the Sedgwick County Zoo specimen (SCZ 4550) is straightforward. It had been acquired from the Cincinnati Zoo, which bought the bird in 1960, four years before Wetmore’s (1964) taxonomic re- vision. It was identified correctly at the time as a yellow-headed vulture (C. burrovianus) and that identification was not changed or updated when the species within that genus were revised. The second specimen (MPEG CH-268) illus- trates the potential pitfalls associated with such similar species. In his study of the birds of the state of Amapa, Novaes (1974) cited one 1902 specimen of Lesser Yellow-headed Vulture from Cunani (02°48'N, 51°06'W, Paynter and Traylor 1991), but could not locate specimens of the Greater Yellow- headed Vulture. Despite the lack of specimens, he felt certain that Greater Yellow-headed Vultures oc- curred in the state at least in the forested western half. The Amapa individual (MPEG CH-268) used in this study was collected specifically for Griffiths’ on-going molecular studies, because at the time the Lesser Yellow-headed Vulture was not repre- sented in any tissue collections. Large open-coun- 186 Griffiths and Bates VoL. 36, No. 3 Table 4. Nucleotide sites that differ in sequences of cytochrome b of Cathartes melambrotus and C. burrovianus and the bird from Amapa, Brazil. The Amapa specimen is identical to C, melambrotus except at a single site (108,5). Specimen Nucleotide Site 72 117 165 195 228 249 273 285 327 396 501 534 594 603 628 648 696 C. melambrotus T C C G C G C T G T A G T A C C G Amapa specimen * * C burrovianus C T T A T A T C A G G A C G T T A 699 747 751 753 801 819 843 858 1038 1050 1062 1085 1107 1113 C melambrotus T C C T C A C C T T A C C A Amapa specimen * T . C burrovianus C T T A T G T T C C G T * G * C. burrovianus KUNHM 89.344 has a T in position 1107. try taxa are not often part of modern collections, and vultures may be among the most under-rep- resented groups in modern avian collections. At the time of collection, this particular individual was perched 4 m above the ground on the edge of a gallery forest next to a seasonally-flooded grassland at Lago Cujubim (1°39'N, 50°55'W). During the previous several days, yellow-headed vultures had been seen soaring low over the adjacent open grasslands. Based on the habitat and the flight be- havior and light primary shafts of a number of in- dividuals, all had been identihed as Lesser Yellow- headed Vultures. There are some fingers of primary forest in the region, but the nearest con- tinuous forest lies some 10 km to the west. Thus, It was assumed that this bird was a Lesser Yellow- headed Vulture. The genetic data clearly refute this and reexamination of the specimen supports the reidentification as a Greater Yellow-headed Vulture. When the problem in the sequences be- came apparent, we reexamined the voucher spec- imens. Morphological mea.surements confirmed the information from the sequence comparisons, that this was, indeed, a Greater Yellow-headed Vul- ture. This specimen (MPEG CH-268) now repre- sents the first documented record of a Greater Yel- low-headed Vulture for Amapa and clearly suggests that this species ventures some distance into the wet grasslands of this region. Debating the value of specimen-based research, of collecting, and, implicitly, of natural history col- lections, is becoming increasingly contentious with- in the scientific community. Editorials and edito- rial policy in leading ornithological journals appear to question various aspects of collecting (British Ornithologists’ Club 2001, British Orni- thologists’ Union 1995). Papers are published ba.sed on sequence data, with little or no infor- mation about the specimens from which the se- quences were derived (Ruedas et al. 2000). That non-specimen based research has the po- tential to be sloppy science, with no opportunity to reexamine or verify data, has been noted (Ruedas et al. 2000) . Comprehensive statements have been published about the importance of voucher speci- mens for accurate scientific work, and the impor- tance of collections for science, in general (e.g.. Winker et al. 1991, Remsen 1995, Winker 1996, Pe- terson et al. 1998, Ruedas et al. 2000). In this re- port, we are not attempting to add to this general review. Rather, we are verifying the necessity of voucher specimens for molecular work. Without the ability to reexamine the specimens, we might have misinterpreted the results from the molecular data used in this study. Acknovutixa-ienis We thank fosc Maria (iardosa da Silva, David Oren, and Dionisio Pimentel lor their efforts in the field in Amapa, Brazil, and for re(;xamining the Amapa specimen at Mu- seu Paraensc Emilio Goeldi (MPEG). We thank the fol- lowing curators and collection managers for providing additional tis.sue sarnplc.s used in this research: Fred Shel- don at the Louisiana State Univer.sity Museum of Natural Science (LSUMNS), [on Seitz at the Sedgwick Co. Zoo (SGZ) in Wichita, Kansas, and Mark Robbins at the Kan- sas State University Museum of Natural History (KMNH). Work in Amapa was supported by Chamflora and a grant to J.M. Cardosa da Silva from Conselho Nacional de De- senvolvimento Gientifico e Tecnologico (Grant no. .802464/88-3). This research is a contribution from the Lewis B. and Dorothy Gullman Research Facility at the American Museum of Natural History and has received generous support from the Lewis B. and Dorothy Cull- man Program for Molecular Systematics Studies, a joint September 2002 Genetics of Cathartes Vultures 187 initiative of the New York Botanical Garden and the American Museum of Natural History, and from the Bi- ology Department of the Brooklyn Campus of Long Is- land University. Literature Cited Blake, E.R. 1977. Manuel of neotropical birds. Vol. 1. Univ. of Chicago Press, Chicago, IL U.S.A. British Ornithologists’ Club. 2001. Editorial. Bull. Br. Ornithol. Club 121:1. British Ornithologists’ Union. 1995. Editorial. Ibis 137:457-458. del Hoyo, J., a. Elliott, andJ. Sargatal. 1994. Hand- book of the birds of the world. Vol. 2. New world vul- tures to guineafowl. Lynx Edicions, Barcelona, Spain. Desjardins, P. and R. Morais. 1990. Sequence and gene organization of the chicken mitochondrial genome: a novel gene order in higher vertebrates. J. Mol. Biol. 212:599-634. DE Schauensee, R.M. 1970. A guide to the birds of South America. Livingston Publishing Company, Wynne- wood, PA U.S.A. AND W.H. Phelps, Jr. 1978. A guide to the birds of Venezuela. Princeton Univ. Press. Princeton, NJ U.S.A. Groth, J.G. 1998. Molecular phylogenetics of finches and sparrows: consequences of character state remov- al in cytochrome b sequences. Mol. Phylogenet. Evol. 10: 377-390. Helm-Bychoswki, K. and J. Cracraft. 1993. Recovering phylogenetic signal from DNA sequences: relation- ships within the corvine assemblage (class Aves) as inferred from complete sequences of the mitochon- drial DNA cytochrome b gene. Mol. Biol. Evol. 10: 1196-1214. Hilty, S.L. and W.L. Brown. 1986. A guide to the birds of Colombia. Princeton Univ. Press. Princeton, NI U.S.A. Houston, D.C. 1994. Observations on Greater Yellow- headed Vultures Cathartes melambrotus and other Ca- thartes species as scavengers in forest in Venezuela. Pages 265-268 in B.-U. Meyburg and R.D. Chancellor [Eds.]. Raptor conservation today. Pica Press, Lon- don, U.K. Novaes, F.C. 1974. Ornitologia do territorio do Amapa I. Publicagoes avulsas do Museu Goeldi 25:1-121. Paynter, R.A., Jr. and M.A. Trayi or, Jr. 1991. Ornitho- logical gazetteer of Brazil. Museum of Comparative Zoology, Cambridge, MA U.S.A. Peterson, A.T., A.G. Navarro-Siguenza, and H. Benitez- Diaz. 1998. The need for continued scientific collect- ing; a geographic analysis of Mexican bird specimens Ibis 140:288-294. Remsen, J.V. 1995. The importance of continued collect- ing of bird specimens to ornithology and bird con- servation. Bird Conserv. Int. 5:145-180. RIDGELY, R.S. AND PJ- Greeneield. 2000. The birds of Ec- uador; status, distribution, and taxonomy. Cornell Univ. Press, Ithaca, NY U.S.A. Ruedas, L.A., J. Saiazar-Bravo, J.W. Dragoo, and T.L. Yates. 2000. The importance of being earnest: what, if anything, constitutes a “specimen examined?’’ Mol. Phylogenet. Evol. 17:129-132. Sick, H. 1993. Birds in Brazil, a natural history. Princeton Univ. Press. Princeton, NJ U.S.A. Wetmore, a. 1964. A revision of the American vultures of the genus Cathartes. Smithsonian Miscellaneous Collec- tions. 146:1—18. Winker, K. 1996. The crumbling infrastructure of biodi- versity: the avian example. Conserv. Biol. 10:703-707. , B.A. Fall, J.T. Klicka, D.F. Parmelee, and H B Tordoef. 1991. The importance of avian collections and the need for continued collecting. Loon 63:238- 246. Zimmer, K.J., A. Whitfaker, and D.C. Oren. 2001. A cryptic new species of flycatcher (Tyrannidae; Suinn) from the cerrado region of central South America. Auk 118:56-78. Received 10 December 2001; accepted 29 April 2002 Associate Editor: Clint Boal J Raptor Res. 36(3);188-193 © 2002 The Raptor Research Foundation, Inc. ORAL ADMINISTRATION OF TILETAMINE/ZOLAZEPAM FOR THE IMMOBILIZATION OF THE COMMON BUZZARD {BUTEO BUTEO) Martin Janovsky,! Thomas Ruf, and Wolfgang Zenker Research Institute for Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse f A- 11 60 Wien, Austria Abstract. — The purpose of this study was to test the efficacy of oral administration of tiletamine/ zolazepam in a bait for immobilizing Common Buzzards (Buteo buteo) {N = 20). Two different dosages and two different methods of administration were compared. A dosage of 80 mg/kg was sufficient in most birds to enable safe handling after 30-60 min, whereas the majority of animals receiving 40 mg/ kg still showed defensive reflexes. Birds receiving the drug in a powder form reached the deepest stage of anaesthesia after 30 min, whereas birds receiving a solution reached this stage significantly later, but not before 60 min. When the prepared bait with 80 mg/kg powder was stored for 7 or 14 hr, respectively, effectiveness of immobilization was significantly decreased compared to bait which was administered immediately after preparation. Keywords: Common buzzard-, Buteo buteo; tiletamine, zolazepam', immobilization-, oral administration-, capture, Zoletil Administracion oral de Tiletamina/zolazepam para la inmovihzacion de Buteo buteo Resumen. — El proposito de este estudio fue el de administrar oralmente tiletamina/ zolazepam en un cebo para la inmovilizadon de Buteo buteo {N = 20). Dos dosificaciones y dos metodos diferentes de administracion fueron comparados. Una dosis de 80 mg/kg fue suficiente en la mayoria de las aves para garantizar una manipulacion segura despues de 30-60 minutos, mientras que la mayoria de los animales que recibieron 40 mg/kg tenian reflejos para defenderse. Las aves que recibieron la droga en forma de polvo alcanzaron los estados mas profundos de anestesia despues de 30 minutos, mientras que las que recibieron en solucion alcanzaron este estado significativamente mas tarde, no antes de 60 minutos. Cuando el cebo con 80 mg/kg de polvo fue almacenado durante 7 o 14 horas respectivamente, la efectividad de la inmovilizadon disminuyo significativamente comparada con el cebo suministrado inmediatamente despues de la preparacion. Raptors have to be captured in a number of dif- ferent situations. Birds which escape from their avi- ary can be dangerous to man, especially if they are imprinted on humans. To prevent such individuals from being killed, they have to be caught imme- diately. For therapeutic reasons, injured or young birds which are not able to migrate have to be cap- tured. For scientific investigations, wild birds have to be immobilized to be marked, measured, trans- ported, or fitted with a transmitter. The well-known inhalation anaesthesia for birds with isoflurane (Hochleithner 1992) cannot be used for these pur- poses. Also, chemical immobilization via tele-injec- tion (Wiesner 1998) with a blow pipe or narcotic ' Present address: Amt der Tiroler Landesregierung, Ve- terinaerdirektion, Wilhelm-Greilstrasse 25, A-6020 Inns- bruck, Austria; e-mail address: m.janovsky@tirol.gv.at [Traduccion de Cesar Marquez] rifle is not suitable for the capture of birds due to the possibility of producing serious injuries. There- fore, mechanical methods for capturing birds, es- pecially nets or different types of snares, are still used. The stress for these animals is inevitable and escape attempts followed by injuries sometimes cannot be avoided. The oral administration of dif- ferent narcotics with a prepared bait was tested in several avian species. Williams and Phillips (1972) tried to catch Rock Doves ( Columba Iwia) using Tri- bromomethanol. The small safety margin of this drug resulted in a mortality rate between 2.9% and 40.6%. Alpha-chloralose, a chloral derivative of glu- cose (Crider and McDaniel 1967) seems to be suit- able for the oral immobilization of Rock Doves (Woronecki et al. 1992, Woronecki and Dolbeer 1994, Belant and Seamans 1999), Wild Turkeys {Meleagtis gallopavd) (Williams 1966), Marabou 188 September 2002 Oral Zoletil Administration to Buzzards 189 Storks {Leptoptilos crumeniferus) (Pomeroy and Woodford 1976), American Crows {Corvus brachyr- hynchos) (Stouffer and Caccamise 1991), and Can- ada Geese {Branta canadensis) (Belant and Sea- mans 1997). Studies on the use of alpha-chloralose in raptors have not been reported. Ketamine, a dis- sociative anaesthetic, can be administered orally in birds and has a wide safety margin (Kosters and Jakoby 1987). This drug has been used successfully in the immobilization of raptors (Van Heerden et al. 1987) and, for instance, a Harris’ Hawk (Para- buteo unicinctus) was immobilized with the oral ad- ministration of ketamine (Garner 1988). However, the use of ketamine alone in birds may lead to convulsions that can be prevented if it is used to- gether with diazepam (Baronetzky-Mercier and Sei- del 1995). The injection of a combination of ke- tamine and climazolam, a potent benzodiazepian derivative, was shown to be effective for the im- mobilization of Common Buzzards {Buteo buteo) (Gutzwiller et al. 1984). The objectives of our study were to assess the suitability of oral administration of tiletamine-zolazepam for the immobilization of Common Buzzards, to find the optimal dosage of different preparations, and to evaluate the loss of effectiveness with storage time of the bait. Tiletam- ine-zolazepam is an injectable anaesthetic combi- nation which provides rapid and smooth induction of anaesthesia (Hui Chu Lin 1996) and has been shown to be effective and safe in many species in- cluding raptors (Schobert 1987). MATERIAI.S AND METHODS Animals. We obtained 20 buzzards for this study from the raptor rehabilitation center, Fuchsenbigl, Austria. Use of animals in this study followed the Austrian law on animal experiments (§ 8 BGBl.Nr. 501/1989, GZ 68.205/ 8v8-Pr/4/96). The raptors were housed in an aviary. Most of these birds had been found injured in the wild, and 18 of the birds were unable to fly. Birds were clinically examined before and after each immobilization, and nei- ther age, sex, or a detailed health status of the animals was known. All the animals were not fed for 24 hr prior to the application of Zoletil® to create standardized con- ditions concerning resorption. For the oral application of the prepared meat the birds were manually restrained. Therefore, the animals were put into a paper box and the wings were held firmly against the body. To observe the induction time the birds were transfered into a sep- arate aviary. Drug and Preparation of the Bait. Zoletil® (Virbac, Garros, France) is a 1:1 combination of tiletamine and zolazepam. Tiletamine is a dissociative anaesthetic with a pharmacological activity similar to ketamine (Lin et al. 1993), but is more potent (Short et al. 1989). Zolazepam is a benzodiazepine agonist and in pharmacological ac- tivity comparable to diazepam (Loescher 1999), For han- dling the drug, the same precautions to avoid misuse or accidental intake by humans must be taken as for other commonly-used anaesthetics. Zoletil® comes as a freeze- dried powder suitable to adhere to different surfaces or to dissolve in solutions up to 33%. This combination is used for many domestic and exotic species (Schobert 1987). It was shown to be suitable to produce anaesthesia in buzzards via intramuscular injection (Trah 1990). Dos- ages for the oral administration of Zoletil® could not be found in the literature. For the oral application, the dry powder was scattered over a piece of rabbit meat or a 10% solution with sterile water was applied on the sur- face of the meat and allowed to dry for 20 min. For the experiments during phase three the prepared meat with Zoletil® was stored for 7 or 14 hr, respectively, at room temperature and daylight. Study Design. Phase one. Test birds were randomly as- signed into two groups. One group {N = 10) was fed meat sprinkled with 40 mg/kg of powdered Zoletil®, while the second group {N =10) was fed meat covered with 40 mg/kg Zoletil® in a 10% solution of sterile water Phase two. Four wk later we repeated the experiment with a dosage of 80 mg/kg. The birds were again ran- domly assigned into one of the two groups. Pha.se three. Six mo later we repeated the experiment with a dosage of 80 mg/kg powdered Zoletil®, however, a pre-administration period of 7 hr for group one and 14 hr for group two was added. Again, the birds were randomly assigned into one of the two groups. Assessment of Depth of Anaesthesia. The depth of an- aesthesia was judged clinically. We used a modified ver- sion of the scale of Gutzwiller (1984): 0 = no effect; 1 = light sedation; 2 = moderate sedation, close approach not possible; 3 = strong sedation, birds able to be han- dled by experienced people; 4 = superficial anaesthesia, birds able to be handled by inexperienced people; 5 = deep anaesthesia. All birds were checked 30, 60, and 90 min after appli- cation of Zoletil® anaesthesia. If approach to and han- dling of the buzzards were possible (stage 3), every check included assessment of heart and respiration rate. In buz- zards which had reached stage 4, the palpebral reflex, corneal reflex, head position, and neck muscle tone were tested additionally. For birds in stage 5, the reflex-moni- toring system of Korbel et al. (1997) was used. Following the last check, the birds were taken out of the aviary and put into a cardboard box where they spent the night, before they were returned to their common aviary. Re- covering birds were checked every 30 min in the card- board box until they returned to stage 0. No more than two animals were immobilized at the same time. Statistics. To test for differences in anaesthesia depth we used a non-parametric analysis of variance for repeat- ed measurements with time course of anaesthesia as the within-subjects factor and dose as well as preparation of Zoletil® as between-subjects factors (Zar 1984). Depth of anaesthesia values were transformed to ranks for analysis To test statistical differences in induction time between baits with different storage time we used two-tailed Mann- Whitney U-tests. Criterion for detection of statistically sig- nificant differences was P ^ 0.05. Animals that died in association with the use of the 190 Janovsky et al. VoL. 36, No. 3 Time (min) ■ 40 mg, powder □ 40 mg, solution • 80 mg, powder O 80 mg, solution Figure 1. Depth of anaesthesia (mean ± SE) 30, 60, and 90 min after receiving oral Zoletil® (0 = no effect; 1 = light sedation; 2 = moderate sedation, close approach not possible; 3 = strong sedation, birds able to be handled by experienced people; 4 = superficial anaesthesia, birds able to be handled by inexperienced people; 5 = deep anaesthesia) . drugs were necropsied following standard protocols (Rof- fe et al. 1996). Necropsy was carried out by the Institute of Pathology at the University of Veterinary Medicine, Vi- enna, Austria. Results The 20 animals receiving 40 mg/kg had signifi- cantly lower mean values of depth of anaesthesia than the animals receiving 80 mg/kg {P < 0.02). Fifteen out of 18 birds receiving 80 mg/kg (83%) reached stage 4, whereas only six out of 20 (30%) birds receiving 40 mg/kg achieved that stage. How- ever, 17 out of 20 (85%) animals of that group reached at least stage 3 (Fig. 1). The administration form had no overall effect on the depth of anaesthesia. However, the time course of anaesthesia depended on the prepara- tion of oral Zoletil®. The groups receiving Zoletil® as a dry powder reached the deepest stage of an- aesthesia with both dosages after 30 min, whereas the groups receiving Zoletil® solution did not reach this stage before 60 min (Fig. 1). This inter- action between administration form and anaesthe- sia time course was significant (P < 0.02). Storage of the drngged bait had a highly signif- icant effect on the depth of anaesthesia (Table 1). Anaesthesia was deeper for fresh baits (P < 0.001) at 30, 60, and 90 min after application compared to the depth reached after administration of the Table 1. Stage of anaesthesia (mean ± SE) 30, 60, and 90 min after receiving oral Zoletil® (0 = no effect; 1 = light sedation; 2 = moderate sedation, close approach not possible; 3 = strong sedation, birds able to be handled by experienced people; 4 = superficial anaesthesia, birds able to be handled by inexperienced people; 5 = deep an- aesthesia) . N Time After Application Time"^ 30 MIN 60 MIN 90 MIN 40 mg/kg powder 10 0 3.0 ± 0.3 2.7 ± 0.4 2.7 ± 0.4 40 mg/kg solution 10 0 2.8 ± 0.4 3.1 ± 0.3 2.9 ± 0.4 80 mg/kg powder 9 0 3.8 ± 0.2 3.7 ± 0.2 3.6 ± 0.2 80 mg/kg solution 9 0 3.2 ± 0.3 3.9 ± 0.2 3.9 ± 0.2 80 mg/kg powder 9 7 1.8 ± 0.3 2.4 ± 0.3 1.8 ± 0.3 80 mg/kg powder 9 14 1.6 ± 0.3 2.1 ± 0.3 1.7 ± 0.3 Storage time (hr). September 2002 Oral Zoletil Administraiton to Buzzards 191 drugged, stored bait. Mean (SE) depth of anaes- thesia was highest 60 min after application with 2.4 and 2.1 for a storage time of 7 and 14 hr, respec- tively. Differences between 7 and 14 hr were not significant. All immobilized birds recovered com- pletely. After 120 min of application, the depth of anaesthesia was <3 in all cases; the no effect level was reached after 5 hr in all except in four animals. These buzzards, two of them receiving 80 mg/kg Zoletil® solution and two 80 mg/kg Zoletil® in a powdered form, respectively, had an 8 hr recovery time before reaching stage 0. Two birds died during this study. Both animals received 40 mg/kg Zoletil® as a solution. One died on the second day after the trial and one after a wk. The first bird showed massive edema of the mandibular space and intranuclear inclusions in renal tubular epithelial cells indicating a viral in- fection of the kidneys of an unknown origin. The second bird had an unremarkable recovery before it suddenly died seven days later. Necropsy of the bird showed severe arteriosclerosis, myocardial de- generation, cardiac insufficiency, and purulent hepatitis. DISC’USSION The combination of tiletamine and zolazepam has a wide safety margin and its use in birds is well documented (Schobert 1987, Blyde 1992, Hayes 1996). The depth of anaesthesia depends on the dose. Dose rates for intramuscular injection in birds range from 2 mg/kg in Common Rheas {Rhea americana) to 75 mg/kg in Green Herons {Butorides virescens) according to Schobert (1987). For buzzards, 14 mg/kg (Gray 1974) or 30 mg/kg (Trah 1990) were recommended. Giving Zoletil® orally seems to have a much wider safety margin according to our results. Therefore, there seems to be little risk for the life of non-target animals, which may accidentally feed on the bait, due to overdosing. However, in general birds were not in a stage of anaesthesia that would allow minor sur- gical procedures, even with a dose of 80 mg/kg. A possible explanation for this observation could be the fact that the breakdown of Zoletil® in the blood starts before the total absorption from the gastrointestinal tract has been completed. The two deaths that occurred during the study were not a consequence of the experiment accord- ing to the post mortem findings. Any kind of an- aesthesia induces a certain amount of considerable stress for each organism, which can lead to pro- gression of preexisting diseases. This might have been the case in the first bird that died. However, 83% of the birds that received 80 mg/kg of the freshly-prepared bait, without storage time, were appropriately immobilized to allow inexperienced people to handle them safely (stage 4), whereas only 30% of the birds receiving 40 mg/kg reached that stage. Nevertheless, the dose of 40 mg/kg would be sufficient to enable handling of buzzaids by experienced people, as 85% of the animals of that group reached at least stage 3. Storage time of the drugged bait reduced the potency of the drugs. A major loss of drug effect occured in the first 7 hr, whereas in the next 7 hr the reduction of efficacy was less. Birds which are anaesthetized using a stored bait were sedated, but could not be handled by experienced people in all cases. Therefore, the drugged bait should be re- placed after several hr if it is not taken by the bird. Although baits were force fed in this study, it is likely that birds will readily accept the prepared bait in one piece as previous experiences with dif- ferent raptors have shown (H. Frey unpubl. data, M. Janovsky unpubl. data) . It is interesting to note that the form of the oral drug (i.e., powder or solution) had a significant effect on the time course of the anaesthesia. The groups receiving Zoletil® in a powdered form reached the deepest stage of anaesthesia after 30 min, whereas the groups receiving Zoletil® solution did not reach this stage before 60 min (Fig. 1). The reason for this phenomenon is not yet clear, but it seems possible that the liquid drug permeates into the bait, whereas, the powder stays on the surface allowing a quicker absorption. Pain sensation in birds is comparable to that in mammals (Gentle 1992). Therefore, surgical procedures should not be carried out if only oral Zoletil® has been administered. In addition, the widespread used cyclohexamines like ketamine or tiletamine do not produce deep enough an- algesia for surgical procedures in birds if used as a monoanaesthetic (Korbel 1998, Korbel et al. 1998). Thus we do not recommend surgery m birds which are immobilized with Zoletil® only. Although most birds recovered completely after 5 hr, full recovery took 8 hr in 4 animals. In prac- tice, drugged birds should be kept isolated at minimum of 24 hr for complete recovery be- cause absorption and metabolization rates vary individually. We conclude that the oral application of liquid 192 Janovsky et al. VoL. 36, No. 3 or powdered Zoletil® in a dosage of 80 mg/kg is an appropriate method to immobilize Common Bnzzards to enable safe handling. The safety mar- gin of the drug combination at oral administration appears to be wide enough for use in capturing Common Buzzards of unknown mass. Acknowledgments Our special thanks go to W. Arnold, head of the Re- search Institute for Wildlife Ecology for supporting this study. We are very grateful to J. Kurzweil from the raptor rehabilitation center for handling and taking care of the birds. We thank D. Bernet and A. Groene for advice in interpretation, Ch. Beigelboeck, M. Froetscher, and W. Laupichler for assistance during the experiments, S. Hoe- gler for necropsies, and to A. Koerber for drawing the figure. This study was supported by the Gesellschaft zur Foerderung des Forschungsinstitutes fuer Wildtierkunde und Oekologie, Vienna. Literature Cited Baronetzky-Mercier, a. and B. Seidel. 1995. Greihogel und Eulen, Pages 443-465 in R. Gdltenboth and H.G. Klos [Eds.], Krankheiten der Zoo- und Wildtiere. Blackwell Wissenschaftsverlag, Berlin, Germany. Beiant, J.L. and T.W. Seamans. 1997. Comparisons of three formulations of alpha-chloralose for immobili- zation of Canada Geese, y. Wildl. Dis. 33:606-610. AND T.W. Seamans. 1999. Alpha-chloralose im- mobilization of Rock Doves in Ohio. J. Wildl. Dis. 35: 239-242. Blyde, D. 1992. Zoletil for anaesthesia in birds. Control and Therapy Series, No. 3294. Univ. of Sydney Post- graduate Committee in Veterinary Science, Sydney, Australia. Crider, E.D. and J.C. McDaniel. 1967. Alpha-chloralose used to capture Canada Geese. J. Wildl. Mana&. 31: 258-264. Garner, M.M. 1988. Use of an oral immobilizing agent to capture a Harris’ Hawk (Parabuteu unicinctus) . J. Raptor Res. 22:70-71. Gentle, M.J. 1992. Pain in birds. Anim. Welf. 1:235-247. Cray, C.W. 1974. Clinical experience using Cl-744 in chemical restraint and anaesthesia of exotic speci- mens./. Zoo Anim. Med. 5:12-21. CUTZWILLER, A,, J. VOLLM, AND B. Hamza. 1984. Einsatz des Benzodiazepins Climazolam bei Zoo- und Wildti- eren. Kleintierpraxis 29:281-340. Hayes, L.M. 1996. Restraint and anaesthesia of wild and domestic birds. Pages 295-315 in Ann. Conf. Proc., Assoc. Avian Veterinarians Australian Committee, Syd- ney, Australia. Hochleithner, M. 1992. Erfahrungen mit der Isofluran- Narkose bei Reptilien und Vogeln. Verhandlungshericht der Erkrankungen der Zootierc 34:171— 177. Hui Chu Lin. 1996. Dissociative anaesthetics. Pages 241- 296 m J.C. Thurmon, W.J. Tranquilli, and C.J. Benson [Eds.], Lumb and Jones’ veterinary anaesthesia. Wil- liams and Wilkins, Baltimore, MD U.S.A. Kosters, J. and J.R. Jaroby. 1987. Enten und Cause. Pag- es 363-399 in K. Cabrisch and P. Zwart [Eds.], Kran- kheiten der Wildtiere. Schliitersche Verlagsanstalt, Hannover, Germany. Korbel, R. 1998. Vergleichende Untersuchungen zur In- halationsanasthesie mit Isofluran (Forene®) und Sev- ofluran (Sevorane®) bei Haustauben {Columba livia Cmel., 1789, var. Domestica) und Vorstellung eines Referenz-Narkoseprotokolls fur Vogel. Tierdrztl. Prax. 26:211-223. , C. Lendl, K. Baumgartner, and A. Gauckler 1997. Referenzschema zur Anasthesie bei Zoo- und Wildvogeln. Verhandlungshericht der Erkrankungen der Zootiere 38:195-204. , J. Kosters, and B. Benedikt. 1998. Schmerz und Analgesic beim Vogel — Eine Ubersicht. DVC-Tagung Vogelkrankheiten, Munchen, Germany. Lin, H.C., J.C. Thurmon, GJ. Benson, and WJ. Tran- QUILLI. 1993. Telazol — a review of its pharmacology and use in veterinary medicine./. Vet. Pharmacol. Ther. 16:383-418. Loescher, W. 1999. Pharmaka mit Wirkung auf das Zen- tralnerven.system. Pages 67-117 in W. Loescher, F.R Ungemach, and R. Krocker [Eds.], Pharmakothera- pie bei Haus-und Nutztieren. Paul Parey, Berlin, Ger- many. Pomeroy, D.E. and M.H. Woodford. 1976. Drug im- mobilization of Marabou Storks, f. Wildl. Manage. 40. 177-179. Roffe, T.J., M. Friend, and L.N. Locke. 1996. Evaluation of causes of wildlife mortality. Pages 324—348 in T.A. Bookhout [Ed.], Research and management tech- niques for wildlife and habitats. The Wildlife Society, Bethesda, MD U.S.A. Schobert, E. 1987. Telazol® use in wild and exotic ani- mals. Vet. Med. 82:1080-1088. Short, C.E., C.H. Tracy, and E. Sanders. 1989. Investi- gating xylazine’s utility when used with telazol in equine anaesthesia. Vet. Med. 86:228-233. Stouffer, P.C. and D.R Caccamise. 1991. Capturing American Crows using alpha-chloralose. /. Field Orni- thol. 50:450-453. Trah, M. 1990. Tilest — Ein neues Narkotikum auch fur die Vogelpraxis? KfemfoA/raxA 35:413-416. Van Heerden, j., j. Komfn, and E. Myer. 1987. The use of ketamine hydrochloride in the immobilization of the Cape Vulture {Gyps coprothere.s) . J. S. Apr. Vet. Assoc 58:143-144. Wiesner, H. 1998. Tierschutzrelevante Neuentwicklun- gen zur Optimierung der Distanzimmobilization. Tier- drztl. Prax. 26:225-233. Williams, L.E., Jr. 1966. Capturing Wild Turkeys with al- pha chloralose./ Wildl. Manage. 30:50-56. AND R.W. Philups. 1972. Tests of oral anaesthetics September 2002 Oral Zoiltil Administration to Buzzards 193 to capture Mourning Doves and bobwhites. J. Wildl. Manage. 36:968-971. WORONECKI, P.P. AND R.A. DoLBEER. 1994. Alpha-chloral- ose: current status, restrictions and future uses for capturing birds. Proc. Vertebr. Pest Conf. 16:255-258. , R.A. Dolbeer, T.W. Seamans and W.R. Lanca. 1992. Alpha chloralose efficacy in capturing nuisance waterfowl and pigeons and current status of FDA reg- istration. Proc. Vertebr. Pest Conf. 15:72-78. Zar, J.H. 1984. Biostatistical analysis. Prentice Hall, En- glewood Cliffs, NJ U.S.A Received 15 April 2001; accepted 8 April 2002 J. Raptor Res. 36(3): 194— 199 © 2002 The Raptor Research Foundation, Inc. HUNTING BEHAVIOR OF AND SPACE USE BY EASTERN SCREECH-OWLS DURING THE BREEDING SEASON Jennifer E. Buhay^ and Gary Ritchison^ Department of Biological Sciences, Eastern Kentucky University, Richmond, KY 40475 U.S.A. Abstract. — The hunting behavior of and space use by radio-tagged Eastern Screech-Owls {Otus asio; three pairs, one unmated male, and four fledglings) were observed in central Kentucky from March- June 1999. Screech-owls perched at a mean height of 2.2 m. The mean giving up time was 340.2 sec, while the mean time until initiating an attack was 361.4 sec. Owls attacked prey located a mean distance of 2.27 m from perches, and the mean distance between successive perches was 10.33 m. Male screech- owls perched higher in taller trees during the fledgling period, and these higher perches were appar- ently used when hunting insects. Male screech-owls also hunted in different areas of their ranges during different breeding periods, possibly to take advantage of temporarily abundant prey and avoid prey depletion. During the fledgling period, the hunting ranges of paired male and female screech-owls overlapped, but males and females did not hunt in areas of overlap at the same time. Key Words: Eastern Screech-Owl, Otus asio; hunting behavior, perch time, range use, breeding season. Comportamiento de caza y uso de espacio de Otus asio durante la estacion reproductiva Resumen. — El comportamiento de caza y uso del espacio de Otus asio dotados con radio transmisores (tres parejas, un macho solitario y cuatro volantones) fue observado el centro de Kentucky desde marzo- junio 1999. Los buhos se posaron en perchas a un altura de 2.2 m. El tiempo de espera fue de 340.2 sec, mientras que el tiempo medio hasta el inicio de un ataque fue de 361.4 sec Los buhos atacaron a presas localizadas a una distancia media de 2.27 m de las perchas y a un distancia media entre perchas sucesivas de 10.33 m. Los machos se ubicaron en las perchas mas altas de arboles grandes, aparente- mente estas fueron utilizadas para la caza de insectos. Los machos tambien cazaron en areas distintas a sus rangos durante las diferentes etapas de su reproduccion, posiblemente para aprovechar la abun- dancia temporal de presas y evitar agotarlas. Durante el periodo del crecimiento del plumaje, los rangos de caza de las parejas se traslaparon pero los machos y hembras no cazaron en areas de traslape al mLsmo tiempo, [Traduccion de Cesar Marquez] Eastern Screech-Owls {Otus asio) are found throughout eastern North America and have been the subject of many studies (e.g., Belthoff et al. 1993, Sparks et al. 1994, Duguay et al. 1997). How- ever, as with other nocturnal predators, direct ob- servations are difficult and, as a result, little is known about the hunting behavior of screech-owls. In one study, Abbruzzese and Ritchison (1997) ob- served the hunting behavior of Eastern Screech- Owls in central Kentucky and found no differences between males and females during the nonbreed- ing season. ' Present address: Department of Biological Sciences, 410 Scientihc Collections, University of Alabama, Tuscaloosa, AL 35487 U.S.A. Corresponding author’s e-mail address: gary.ritchison® eku edu As the breeding season approaches, males and females in many owl species exhibit a division of labor (Reynolds and Linkhart 1987). The repro- ductive success of male raptors may depend on their ability to supply food for mates and offspring throughout the breeding season, beginning with courtship and continuing through the post-fledg- ing period. Once young are able to thermoregu- late and manipulate prey, females resume hunting and assist the male in provisioning nestlings and fledglings (Hovis et al. 1985, Gehlbach 1994). The changing roles of male and female screech-owls during the breeding season may influence their hunting behavior. Our objective with this study was to examine how changing food demands and the changing roles of male and female Eastern Screech-Owls might influence hunting behavior and space use during the breeding season. 194 September 2002 Screech-Owl Hunting Behavior 195 Methods and Materials The hunting behavior of Eastern Screech-Owls (three breeding pairs, an unpaired male, and four fledglings) was studied from 5 March-8 June 1999 at the Central Kentucky Wildlife Management Area, located 17 km southeast of Richmond, Madison County, Kentucky. Adult screech-owls were captured by checking nest boxes or by luring them into mist nets using the playback of bounce songs (Ritchison et al. 1988). Captured owls were fitted with 5-6 gm (about 3-4% of screech-owl body mass) radio-tran.smitters with activity switches (Wildlife Materials, Inc., Carbondale, IL) attached backpack style (Smith and Gilbert 1981). Yellow reflective tape (about 5X1 cm) was attached to the antennas of the transmit- ters to make it easier to locate hunting owls. Owls were allowed 1 wk to become accustomed to the transmitters before observations began. Several days prior to antici- pated fledging dates, nestlings {N = 13 in three nests) were banded with a numbered aluminum leg band, and four (two from one nest and one each from the other two nests) were htted with radio-transmitters. One or two radio-tagged owls were observed each night and general locations were determined using a re- ceiver (TR-2, Telonics Inc., Mesa, AZ) and a hand-held, two-element yagi antenna. Specific locations of owls were determined using a red-tinted flashlight. Owls were as- sumed to be hunting when their attention appeared to be focused on the ground (probably searching for ground-based prey) or on nearby vegetation (probably searching for birds or insects) or flying insects. When hunting, owls also exhibited frequent head movements. In addition, hunting fledglings, in contrast to non-hunt- ing fledglings, were always perched several meters away from siblings. Observations were made at least four times per week. Observation periods started shortly after sunset and were usually 3-4 hr in duration. We typically watched owls from a distance of 8-12 m. Adult females were difficult to observe during the nestling period because they often responded aggressively. Once females began hunting fur- ther away from nest sites (about 1 wk after young fledged), our presence seemed to have little effect on their behavior, As a result, only female hunting perches located during the fledgling period were used in analyses of hunting behavior. The breeding status of each pair was categorized as: pre-nesting, egg-laying/incubation, nest- ling, or fledgling. During focal owl observations, we tape-recorded all in- formation and perches and attack sites were marked with flagging (placed several meters away) for later analysis. Perch times were classified as either giving-up time (the owl flew to another perch without initiating an attack) or time until attack. These times were only determined when we either observed owls landing on a perch or could estimate landing time based on a change in a trans- mitter’s pulse rate (all transmitters had activity switches) . Within 2 wk, we returned to perches and measured perch height, substrate (tree, shrub, or vine) height, the distance from the tree trunk to the perch, and the di- ameter at breast height (DBH) of the perch tree. We also noted tree species and measured the distance to the next perch. If successive perches were more than 50 m apart. we determined the distance using ArcView 3.1 (Environ- mental Systems Research Institute, Redlands, CA) . The location of each perch was recorded in Universal Transverse Mercator (UTM) coordinates using Global Positioning System (GPS) receivers (Garmin XLS). To determine the size of the areas used by owls, we pro- duced 100%-minimum-convex polygons (MCP) using ArcView 3.1 with the Spatial Tools and Animal Movement extensions. We also measured the distance from each perch to the nest in each territory. Repeated measures analysis of variance was used to ex- amine the possible effects of breeding period on the hunting behavior of male screech-owls. Small sample siz- es precluded comparison of male hunting behavior to that of females and fledglings. All analyses were con- ducted using the Statistical Analysis System (SAS Institute 1989). All values are presented as mean ± standard error. Individual owls are referred to by the last three digits of their (or their mate’s or parents’) radio-transmitter fre- quency. Results Eastern Screech-Owls (N = 4 males, 3 females, and 4 fledglings of unknown sex) were observed for a total of 182 hr on 55 nights from 5 March-8 June 1999. Overall, these owls perched at a mean height of 2.20 ± 0.08 m (A^ = 304 perches) in trees with a mean height of 5.63 ± 0.24 m (N = 301 perches) and mean DBH of 0.12 ± 0.01 m (N — 301 perches; Table 1). Owls (N = 11) perched a mean distance of 0.51 ± 0.05 m (A^ = 302 perches) from the main trunk of perch trees or snags. Forty different plant species were used as perches by screech-owls, with snags (21.6%), American ash (11.1%, Fraxinus americano), and American syca- more (7.8%, Platanus occidentalis) used most fre- quently. The mean giving-up time {N = 231 perches of 9 owls) was 340.2 ± 18.7 sec, while the mean time until initiating an attack {N =18 perches of 6 owls) was 361.4 ± 32.0 sec. Owls {N — 6) attacked prey located a mean distance of 2.27 ± 0.28 m from perches {N = 21). The mean distance between suc- cessive perches was 10.33 ± 1.42 m {N = 65 perch changes by 9 owls). We observed 21 attacks by screech-owls, with 11 successful and 10 unsuccessful. Eight of 18 attacks by males were successful, resulting in the capture of three birds, one small mammal, two crayfish (Cambarus spp.), and two insects. Attacks by fe- males {N = 2) and fledglings (N = 1) on insects were all successful. Although adult females and their young were only observed hunting during the fledging period, two males were observed during the pre-nesting, 196 Buhayand Ritchison VoL. 36, No. 3 Table 1. Perch characteristics and hunting behavior of male, female, and fledgling (unknown sex) Eastern Screech- Owls. Values are presented as mean ± one standard error. Sample sizes are in parentheses. Mai.es (N= 4) Females {N= 3) Fledglings {N= 4) Perch height (m) 1.93 ± 0.07 (258) 3.50 ± 0.36 (22) 3.99 ± 0.34 (24) Tree height (m) 4.70 ± 0.22 (255) 9.79 ± 0.92 (22) 11.67 ± 0.79 (24) Distance from tree trunk (m) 0.42 ± 0.05 (256) 0.97 ± 0.27 (22) 0.97 ± 0.23 (24) Tree DBH (m) 0.10 ± 0.01 (255) 0.19 ± 0.03 (22) 0.23 ± 0.05 (24) Distance to next perch (m) 11.07 ± 1.72 (53) 2.25 ± 0.48 (2) 8.75 ± 1.53 (10) Attack distance (m) 2.32 ± 0.30 (18) 0.75 ± 0.25 (2) 2.5 (1) Giving-up time (sec) 355.5 ± 20.4 (201) 183.2 ± 62.4 (13) 279.9 ± 52.0 (17) Attack time (sec) 381.3 ± 32.3 (16) 150 (1) 255 (1) egg-laying/incubation, nestling, and fledgling pe- riods and a third male was observed during all but the pre-nesting period. Analysis of the hunting be- havior of these males revealed that mean perch height (/3 5 = 14.85, P = 0.006) and tree height (^3,5 = 7.99, P = 0.024) varied among periods (Fig. 1 ) , with males perching higher in taller trees dur- ing the fledgling period (Tukey’s test, P < 0.05). We found no differences among breeding periods m other variables, including DBH of perch trees (7^ 5 — 2.43, P = 0.18), distance of perches from the main trunk = 3.5, P = 0.11), giving-up time (7^3 5 = 0.71, P — 0.59), and distance between successive perches (7^2,3 = 2-07, P = 0.27) . Sample sizes were too small to examine possible differenc- Pre-nesting Egg-laying/ Nestling Fledgling Incubation Period Figure 1. Variation among breeding periods in mean perch heights of and trees used by male Eastern Screech- Owls. es among periods in either attack time or attack distance. For male screech-owls, the mean distance of hunting perches from nest sites did not differ (7^3 5 = 0.1, P = 0.95) among breeding periods. Similar- ly, the size of male hunting ranges did not vary (F'g 5 = 4.13, P = 0.056) among breeding periods. How- ever, specific hunting areas used by male screech- owls did vary among breeding periods. For exam- ple, male 957 hunted primarily in the northeastern portion of his territory during the pre-nesting pe- riod, but in the southwestern section during the egg-laying/incubation period. During the nestling period, male 957 hunted primarily in the south- eastern section of his territory and, during the fledgling period, again used the southwestern sec- tion (Fig. 2). Based on a limited number of observations, the Figure 2. Variation in areas used by screech-owl male 957 during different breeding periods in central Ken- tucky. September 2002 Screech-Owl Hunting Behavior 197 sizes of hunting ranges of the three adult female screech-owls during the fledgling period were 7.0 ha (two observation periods, five perches), 9.4 ha (two observation periods, 12 perches), and 12.2 ha (five observation periods, 10 perches), respectively. During the fledgling period, the hunting range of male 957 completely encompassed that of his mate, while the ranges of males 997 and 037 in- cluded 87% and 59% of the hunting ranges of fe- males 997 and 037, respectively. Although ranges overlapped, paired males and females were not ob- served hunting in the same locations on the same night. Fledglings {N — 4 from three different broods) were observed during 10 observation periods (from the day of fledging through 29 d post-fledg- ing) . Young owls were first observed hunting 26 d after fledging. The hrst (and only observed) suc- cessful attack by a fledgling was 27 d after fledging. Discussion Eastern Screech-Owls in our study perched at a mean height of 2.2 m. Similarly, Gehlbach (1994) found that Eastern Screech-Owls in suburban Waco, Texas, hunted from perches at a mean height of 2.6 m. However, at the same location where we conducted our study, Abbruzzese and Ritchison (1997) reported a mean perch height of 1.66 m for screech-owls during the non-breeding season. The higher mean perch height in our study may be due to seasonal differences in the types of prey being hunted and seasonal differences in veg- etation height. During the non-breeding season, screech-owls in central Kentucky appeared to be hunting primarily crayfish and small mammals (Abbruzzese 1996). In contrast, screech-owls in our study often appeared to be hunting for insects, and owls may perch higher when hunting insects to in- crease the visual search area and to scan areas above vegetation for flying insects. For example. Village (1990) noted that Eurasian Kestrels {Falco tinnunculus) chose higher perches when hunting invertebrates because such perches provide larger scanning areas than low perches. During the breeding season, vegetation is taller and thicker than during the non-breeding season and, in response, screech-owls may perch higher. Similarly, Morrison (1980) found that Loggerhead Shrikes (Lanius ludovicianus) selected higher perches during the summer than during the winter because such perches provide a wider field of view in taller, more dense summer vegetation. Other nocturnal owls hunt from perches at heights similar to those used by screech-owls in our study. For example, Boreal Owls {Aegolius funereus) have been reported to hunt from perches at mean heights of 1.7 m (Norberg 1987) and 3.1 m (Bye et al. 1992). Lower perches may provide a better view of ground-dwelling prey in areas where low- growing cover and shrubs obscure much of the ground (Norberg 1987). In addition, low perches may allow owls to better locate prey using acoustic cues (Norberg 1987, Abbruzzese 1996). The mean giving-up time for screech-owls in our study was 340.2 sec (or 5.7 min). Abbruzzesse and Ritchison (1997) reported a mean giving-up time of 278.9 sec (4.6 min) for Eastern Screech-Owls during the non-breeding season, while Gehlbach (1994) found that screech-owls hunting primarily insects had a mean giving-up time of just 72 sec (1.2 min). Gehlbach (1994) suggested that prey abundance influences giving-up times, with owls able to assess areas of dense prey more quickly. Differences in the type of prey being hunted may also influence giving-up times. For example, Bye et al. (1992) suggested that owls need more time to search for small mammals than other prey because their movements are difficult to detect. The mean time before initiating an attack by screech-owls in our study was 361.4 sec (or 6 min), similar in duration to the mean giving-up time (340.2 sec). During the non-breeding season, Ab- bruzzese and Ritchison (1997) also reported no difference between giving up and attack times for screech-owls, and suggested that predators detect- ing invertebrate prey do not wait long before ini- tiating an attack because such prey are relatively easy to capture. In addition, we observed screech- owls capturing or attempting to capture flying in- sects on several occasions. Because flying prey can quickly move out of range, owls likely attack such prey shortly after detection. In contrast, Bye et al. (1992) suggested that Boreal Owls had longer at- tack, or detection, times because they waited lon- ger before initiating attacks on small mammals. Owls attacking small mammals may wait longer be- cause such prey are difficult to capture (Toland 1987, Bye et al. 1992, Atkinson and Cade 1993). Hayward and Hayward (1993) noted that, after de- tecting prey, Boreal Owls sometimes waited 10 min or more if a prey item was not in a vulnerable po- sition. Paired males in our study perched higher in tall- er trees during the fledgling period than during 198 Buhayand Ritchison VoL. 36, No. 3 the pre-nesting and eggdaying/incubation periods. This increase in perch height may have been due to a change in the type of prey being hunted. Male screech-owls appeared to hunt primarily small mammals and crayfish during the pre-nesting and egg-laying/ incubation periods, but were only ob- served hunting insects during the fledgling period. Although this switch may have been due in part to changes in availability, other factors may have also contributed. Gehlbach (1994) suggested that male screech-owls provision females with large prey items during the pre-nesting period because fe- males require substantial amounts of energy to produce a clutch of eggs. However, during the nestling and fledgling periods, male screech-owls may provide their young with smaller, more easily- handled prey like insects (Gehlbach 1994). Mc- Clain (1997) found that adult screech-owls deliv- ered primarily small prey items (including beetles [Coleoptera] and moths [Lepidoptera] ) to nest- lings. Male screech-owls in our study were observed hunting in different parts of their ranges during different breeding periods. One possible reason for such shifts may be to take advantage of tem- porarily abundant prey. For example, Gehlbach (1994) observed that screech-owls sometimes made repeated trips to and from concentrations of in- vertebrates such as emerging cicadas (Gicadidae) and earthworms (Lumbricidae) . Village (1990) noted that raptors sometimes return to hunting sites where prey have been captured. Similarly, we sometimes observed male screech-owls make re- peated visits to the edges of temporary pools and intermittent streams, possibly searching for cray- hsh that were sometimes abundant at such loca- tions (pers. observ.). Abbruzzese (1996) also re- ported that screech-owls in central Kentucky frequently hunted for crayfish. Another reason why male screech-owls might hunt in different areas at different times is to avoid depletion of prey re- sources. For example, Village (1990) found that the hunting ranges of Eurasian Kestrels were not used uniformly and that kestrels were familiar with their territories and the prey resources, as shown by the use of the same hunting locations on suc- cessive days. The hunting ranges of paired male and female Eastern Screech-Owls in our study overlapped, par- ticularly around nest sites. However, our observa- tions also suggest that members of a breeding pair did not use the same hunting locations on the same nights. Other investigators have also found that paired male and female raptors forage in dif- ferent areas probably to avoid competition and prey depletion (Newton 1986, Craig et al. 1988, Village 1990, Gehlbach 1994). Gehlbach (1994) observed that male and female screech-owls leav- ing nest sites on hunting forays usually flew in dif- ferent directions. Similarly, male and female Eur- asian Sparrowhawks {Accipiter nisus) typically hunt in different directions from the nest (Newton 1986, Selas and Rafoss 1999). We first observed hunting by fledgling screech- owls 26 d after fledging. However, we only ob- served the four radio-tagged fledglings on four oc- casions during the period from 16-26 d post-fledging (on days 16, 19, 22, and 26). Gehl- bach (1994) reported that young screech-owls at- tempt to capture insect prey just 9-14 d after fledg- ing and are able to feed themselves regularly 3-4 wk after fledging. Acknowledgments We thank Meg Bommarito, Kevin DeFosset, Matt Rick- etts, and Sue Anestis for help with field work, and Jim Belthoff, Jeff Duguay, and Fred Gehlbach for their many helpful comments on the manuscript. The Frank M. Chapman Fund of the American Museum of Natural His- tory and the University Research Committee at Eastern Kentucky University provided financial support. Literature Cited Abbruzzese, C. 1996. The hunting behavior of Eastern Screech-Owls. M.S. thesis. Eastern Kentucky Univer- sity, Richmond, KY U.S.A. Abbruzzese, C. and G. Ritchison. 1997. The hunting be- havior of Eastern Screech-Owls ( Otus asio). Pages 21- 32 mJ.R. Duncan, D.H. Johnson, and T.H. Nicholls [Eds.], Biology and conservation of owls of the north- ern hemisphere. Gen. Tech. Rep. NC-190. USDA, For- est Service, North Central Research Station, St. Paul, MN U.S.A. Atkinson, E.C. and T.J. Cade. 1993. Winter foraging and diet composition of Northern Shrikes in Idaho. Con- dor 95:528-535. Belthoff, J.R., E.J. Sparks, and G. Ritchison. 1993. Home ranges of adult and juvenile Eastern Screech- Owls: size, seasonal variation and extent of overlap./. Raptor Res, 27:8-15. Bye, F.N., B.V, Jacobsen, and G.A. Sonerud. 1992. Au- ditory prey location in a pause-travel predator: search height, search time, and attack range of Tengmalm’s Owls (Aegolius funereus) . Behav. Ecol. 3:266-276. Craig, E.H., T.H. Craig, and L.R. Powers. 1988. Activity patterns and home-range use of nesting Long-eared Owls. Wilson Bull. 100:204-213. Duguay, T.A., G, Ritchison, and J.P. Duguay. 1997. The September 2002 ScREECH-Owi. Hunting Behavior 199 winter roosting behavior of Eastern Screech-Owls in central Kentucky./. Raptor Res. 31:260-266. Gehlbach, F.R. 1994. The Eastern Screech-Owl: life his- tory, ecology, and behavior in the suburbs and coun- tryside. Texas A&M Univ. Press, College Station, TX U.S.A. Hayward, G.D. and P.H. Hayward. 1993. Boreal Owl {Ae- golius funereus). In A. Poole and F. Gill [Eds.]. The birds of North America, No. 63. The Academy of Nat- ural Sciences, Philadelphia, PA and The American Or- nithologists’ Union, Washington, DC U.S.A. Hovis, J., T.D. Snowman, V.L. Cox, R. Fay, and K.L. Bild- STEiN. 1985. Nesting behavior of Peregrine Falcons in west Greenland during the nestling period. Raptor Res. 19:15-19. McClain, W.R. 1997. Parental investment by Eastern Screech-Owls (Otus asio): the roles of males and fe- males in feeding nestlings. M.S. thesis. Eastern Ken- tucky University, Richmond, KY U.S.A. Morrison, M.L. 1980. Seasonal aspects of the predatory behavior of Loggerhead Shrikes. Condor 82:296-300. Newton, 1. 1986. The sparrowhawk. T & A.D. Poyser, London, U.K. Norberg, N.A. 1987. Evolution, structure, and ecology of northern forest owls. Pages 9-43 in R.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Hamre [Eds.]. Biology and conservation of northern forest owls. Gen. Tech. Rep. RM-142. USDA, Eorest Service, Rocky Mountain Forest and Experiment Station, Fort Collins, CO U.S.A. Reynolds, R.T. and B.D. Linkhart. 1987. The nesting biology of Flammulated Owls in Colorado. Pages 239— 247 in R.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Hamre [Eds.], Biology and conservation of northern forest owls. Gen. Tech. Rep. RM-142. USDA, Forest Service, Rocky Mountain Forest and Experiment Sta- tion, Fort Collins, CO U.S.A. Ritchison, G., P.M. Cavanagh, J.R. Belthoff, and EJ. Sparks. 1988. The singing behavior of Eastern Screech-Owls; seasonal timing and response to play- back of conspecific song. Conc^or 90:648-652. SAS Institute. 1989. SAS user’s guide: statistics. 1989 ed. SAS Institute, Cary, NC U.S.A. Selas, V. and T. Rafoss. 1999, Ranging behavior and for- aging habitats of breeding sparrowhawks {Accipiter ni- sus) in a continuous forested area in Norway. Ibis 14L 269-276. Smith, D.G. and R. Gii.BERT. 1981. Backpack radio trans- mitter attachment success in screech owls ( Otus asto) . N. Am. Bird Bander 6:142-14^3 . Sparks, E.J.,J.R. Belthoff, and G. Ritchison. 1994. Hab- itat use by Eastern Screech-Owls in central Kentucky. /. Field Ornithol. 65:83-95. Toland, B.R. 1987. The effect of vegetative cover on for- aging strategies, hunting success and nesting distri- bution of American Kestrels in central Missouri J. Raptor Res. 21:1 4-20. Village, A. 1990. The kestrel. T. & A.D. Poyser, London, U.K. Received 13 November 2001; accepted 16 April 2002 Former Associate Editor: Cole Crocker-Bedford Short Communications J Raptor Res. 36(3):200-202 © 2002 The Raptor Research Foundation, Inc. SCHIZOCHROMISM IN A PEREGRINE FALCON FROM ARIZONA David H. Ellis’ uses Patuxent Wildlife Research Center, HC 1 Box 4420, Oracle, AZ 85623 U.S.A. Lynn W. Oliphant Department of Veterinary Anatomy, University of Saskatoon, Saskatoon, Saskatchewan, S7N OWO Canada James K. Fackler 5888 Inez Street, Bow, WA 98232 U.S.A. Key Words; Peregrine Falcon', Falco peregrinus; albinism', leuctsm; schizochromism', cannibalism. Herein, we report the first record of schizochromism m the Peregrine Falcon {Falco peregrinus). Our example IS a nestling from southern Arizona. The lack of dark brown pigment in this bird made it closely resemble the blue-gray plumage of an adult. Near fledging time, the bird was eaten by its nestmates, so this article also docu- ments cannibalism. Abnormal pigmentation in wild birds is unusual (but see Fitzpatrick [1980] for a species in which white patch- es are common), but aberrant, pale individuals have been reported for many species (Sage 1962, Ross 1973). A BIOSIS search of the literature for only a 6-yr period located over 100 titles dealing with abnormal plumage in wild birds, Incomplete pigmentation can take many forms. True or complete albinos lack all pigment, not only in plum- age but also in talons and iris. Incomplete albinos usually have patches of white feathers in otherwise normal plum- age Schizochromism is the condition in which one or more pigments are lacking, while others are expressed. Sage (1962) mentions a Green Woodpecker {Picus viri- dis) which was pure white except for its red crown. Some forms of polymorphism are probably derived from some form of albinism. A notable example is the pallid morph of the austral Peregrine Falcon (F. p. cassini) of southern South America (Ellis and Peres Garat 1983). In this morph, juvenile and adult birds weakly express the nor- mal color pattern (bars, streaks, etc.), but have much less pigmentation everywhere (a condition termed leucism), especially in the areas that are lightest in normal pere- grines. In pallid falcons, even the talons and bill, black and deep blue in a normal peregrine, are blond. 'E-mail address: dcellis@theriver.com There are a few published accounts of albinism in the Peregrine Falcon. McGregor (1900) noted a juvenile peregrine with two white secondaries (an example of in- complete albinism) in California. A nearly pure white adult from Devonshire, England is housed at the Amer- ican Museum of Natural History (specimen no. 453937). Sage (1962) included the Peregrine Falcon on the list of species for which albinism is known for the British Isles. On 17 July 1978, we entered an eyrie in southern Ar- izona (32-33°N, 110-111°W) where at least three nor- mally pigmented young had fledged about 6 wk earlier. Conspicuously scattered along the eyrie shelf and con- spicuous below the eyrie were hundreds of feathers, all still in the blood (i.e., all partially grown), of a pale nest- ling that died at about 5 wk of age. Feathers matching this bird (and at least one peregrine talon) were also found in castings on the eyrie shelf. We retrieved as many feathers as practical (at least 374 feathers, excluding down) . When these were assembled, we determined that they represented a single bird (i.e., we found 14 prima- ries, 9 secondaries, and 5 rectrices, none of which were duplicates). On the cover of this issue, an array of these are displayed around an illustration of this young falcon, as it would have appeared in life. Many feathers of this bird show pale brown (buff) spots where such would occur on a normal juvenile. Other feathers have reddish tips just as for normal peregrine juveniles. These same feathers, however, are pale bluish gray, where in a normal juvenile, they would be deep chocolate brown. The extensively gray contours result in this bird more closely resembling an adult than a juve- nile. Because of this resemblance we suspect that this nestling, when it reached this level of development, dis- played enough of the adult sign stimuli that one of its parents responded as if it was an intruding adult and killed it. We cannot be certain that the pale bird was killed by its own family, but tbe presence of feathers and 200 Short Communica.tions 201 September 2002 Figure 1. A comparison of feathers representing various body areas for the nestling displaying schizochromism (right feather in each pair) and two normally-pigmented nesdings (left feathers) from Arizona that died in approximately the same stage of development. Illustrated topographic regions include (left to right, top to bottom): primary flight feather, secondary flight feather, central rectrix, flank, alula, lateral rectrix. Feathers for the pale bird were normal in shape, so the shape differences between the pale and normal feathers in each pair are due to peculiarities associated with exact locus. For example, the pale secondary has a more symmetrical vane tip showing that it is from a more distal follicle than the normally-pigmented secondary. Also, the lateral rectrices are from opposite sides of the tail. 202 Short Communications VoL. 36, No. 3 a talon in castings on the eyrie ledge demonstrate that it was eaten by the family. Also, the excellent condition of Its feathers (i.e., few fault bars and none of great extent) suggest that it was healthy until the time of death. While this individual can be called partially albino (i.e., some dark pigment is lacking) or leucistic (i.e., showing color dilution), a better term for its condition is schizo- chromism (literally: split coloration). Traditionally, this term has been spelled schizochroism (see Van Tyne and Berger 1976:160, Hailman and Emlen 1985), but a sec- ond “m” is obviously needed (chroma: Greek, color; chromatic: English, relating to color). Such birds have some pigments, but not others. Our specimen was nor- mal for buff and reddish brown (Fig. 1) but lacked deep chocolate brown, the most expansive color in the plum- age of normal juveniles. Four clues lead us to conclude that the bird was eaten by falcons on the ledge. First, and most convincing, a talon and many small feathers were found in castings. Second, most of the remains were found on the eyrie ledge (a mammalian predator would likely have removed the carcass to consume it elsewhere) . Third, the feathers were plucked and scattered (as is characteristic of rap- torial bird kill sites) , rather than chewed off and matted with blood and saliva (as is typical of mammalian kills). Finally, at least three young fledged from the eyrie: it is unlikely that the pale bird was taken and eaten by a pred- ator of another species on the eyrie shelf without the predator killing additional nestlings. All of these facts provide evidence that the pale nestling was consumed by Its own family. Cannibalism has previously been docu- mented for five species of falcons including the pere- grine (Ellis et al. 1999). Feathers from this specimen, representing a wide range of topographic regions, were deposited in the Uni- versity of Arizona ornithological collection (UA no. 17828). Resumen. — Un pichon muy palido de Halcon peregrine (Falco peregrinus) fue recuperado muerto en un nido al sur de Arizona. De las plumas y una garra encontrados en una egagropila ubicada al borde de un nido al sur de Arizona, al borde del nido, concluimos que hubo cani- balismo por parte de su propia familia. El plumaje de esta ave mostraba una ausencla del marron oscuro, pre- sentando un manto de color gris palido sin diferencia al del adulto. Este es un ejemplo de esquizocromismo. Todo parece indicar que este fenomeno no habia sido reportado en la bibliografia de la especie. [Traduccion de Cesar Marquez] Acknowledgments Our 1978 research efforts in Arizona were funded pri- marily by the U.S. Forest Service through the Rocky Mountain Forest and Range Experiment Station. We ex- press our appreciation to John Schmitt for the cover painting. This manuscript benefitted from reviews by TJ. Cade, R.W. Nelson, and R. Ritchie. Our thanks to each We express appreciation to William Campbell and Patrick Coronado, both of NASA-Goddard Space Flight Center, for arranging funding for publication of the color fig- ures. Literature Cited Ellis, D.H. and C. Peres Garat. 1983. The pallid falcon Falco kreyenborgi is a color phase of the austral Pere- grine Falcon {Falco peregrinus cassini). Auk 100:269- 271. , P.L. Whitlock, P. Tsengeg, and R.W. Nelson 1999. Siblicide, splayed-toes-flight display, and grap- pling in the Saker Falcon./. Raptor Res. 33:164—167. Fitzpatrick, J.W. 1980. A new race of Atlapetes leucopterus, with comments on widespread albinism in A. 1. dressen (Taezanowski) . Auk 97:883-887. Hailman, J.P. and J.T Emlen. 1985. A fawn-colored Black Vulture in Glades Gounty, Florida. Fla. Field Nat. 13. 20 . McGregor, R.C. 1900. A list of unrecorded albinos. Con- dor 11:86-88. Ross, C.C. 1973. Some additional records of albinism in North American birds. Cassinia 54:18-19. Sage, B.L. 1962. Albinism and melanism in birds. Br. Birds 55:201-225. Van Tyne, J. and A.J. Berger. 1976. Fundamentals of or- nithology. 2nd Ed. John Wiley, New York, NYU.S.A. Received 30 July 2001; accepted 14 April 2002 /. Raptor Res. 36(3):203-206 © 2002 The Raptor Research Foundation, Inc. Natal Dispersal of the Crested Caracara ( Caracara cherjway) in Florida Nicole M. Nemeth College of Veterinary Medicine and Biomedical Science, Colorado State University, Ft. Collins, CO 80523-1601 U.S.A. Joan L. Morrison^ Department of Biology, Trinity College, 300 Summit St., Hartford, CT 06106-3100 U.S.A. Key Words: Crested Caracara; Caracara cheriway; natal dispersal; Florida. The process of dispersal has important implications for the distribution, regulation, and genetic structure of avi- an populations (Greenwood 1980, Greenwood and Har- vey 1982, Paradis et al. 1998). Natal dispersal, movement of an individual from its site of birth to the site of first reproduction or potential reproduction, and breeding dispersal, movement of adult individuals between breed- ing sites (Howard 1960, Greenwood 1980), are m^or agents of gene flow that affect overall population relat- edness and distribution. Understanding how dispersal in- fluences population dynamics is necessary when assessing population responses to landscape change and when de- veloping conservation plans for populations or species. Because of the difficulty in obtaining dispersal data for large, wide-ranging species, information about dispersal in many birds is limited. This is generally true for raptors, which typically have large geographic distributions and range across wide areas. In addition, many raptors do not breed for several years post-fledging; hence, keeping track of individuals through this time period until they begin breeding is difficult for most populations. Here, we report the first information on dispersal for the Crested Caracara {Caracara cheriway), a medium-sized raptor that inhabits open grasslands and pastures (Mor- rison 1996). In North America, extant populations of the Crested Caracara occur only in Florida, Texas, and Ari- zona. Despite this species’ wide geographic range (Mor- rison 1996), many aspects of its biology remain poorly understood, perhaps because of its reputation as a pest throughout much of its Central and South American range, where it is more abundant. Recent widespread loss of grassland and pasture habi- tats in Florida due to agricultural and urban expansion is perceived as a major threat to the persistence of this population of caracaras. These habitat changes and con- comitant population decline (Millsap 1989, Layne 1996) led to listing of this population as federally threatened (U.S. Fish and Wildlife Service 1987). To better under- stand the caracara’s biology and population responses to landscape change, a study of this non-migrator y and iso- ^ Corresponding author’s e-mail address: joan.morrison® trincoll.edu lated population was initiated in 1994 (Morrison 1998, 1999, Morrison and Humphrey 2001). Study objectives included obtaining information about demographic pa- rameters and habitat use. This paper presents informa- tion collected on dispersal of known individuals from their natal site to a breeding site witbin the study popu- lation. Methods The study area incorporated all or parts of eight coun- ties in the south-central peninsula and represents ca. 80% of the caracara’s current breeding range in Florida (Morrison 1999). Our sample included breeding areas that were located throughout this range, but because most of Florida’s caracaras currently live on privately- owned lands (Morrison and Humphrey 2001), efforts to obtain a systematic, random sample of breeding areas or to survey the entire study area were constrained by our ability to secure access from landowners. Crested Caracaras nest primarily from December-April in Florida (Morrison 1999). We began marking nestling caracaras during the 1993-94 breeding season and con- tinued through the subsequent three breeding seasons, 1994-95, 1995-96, and 1996-97. Nestlings were marked at 6-8 wk of age while still in the nest, or just after fledg- ing, when they could be caught easily on the ground Each nestling was marked with a standard numbered U S Fish and Wildlife Service aluminum band and an alumi- num color band with a unique alpha-numeric code (ACRAFT, Inc., Edmonton, Alberta, Canada). The gen- der of marked individuals was determined by DNA anal- ysis of blood samples taken at the time of banding (Mor- rison and Maltbie 1998). To obtain demographic information for this popula- tion, we monitored nesting activity annually. We moni- tored 48 breeding areas during the 1994-95 breeding season and 55 breeding areas during each subsequent year through the 1999-2000 breeding season. During the 2000-01 and 2001-02 breeding seasons, we monitored activity in 15 breeding areas, a subset of the original sam- ple; these breeding areas were located along the Kissim- mee River in the core of the caracara’s current range. Each year, along with collecting information on nesting success and productivity, we identified adults nesting in each breeding area by reading their leg bands with bin- oculars or a spotting scope. Thus, data on dispersal and recruitment were collected opportunistically, incidental to routine annual nest monitoring efforts. We calculated dispersal distance as the straight-line dis- tance between the nest where the individual hatched and 203 204 Short Communications VoL. 36, No. 3 Table 1. Summary of marked juvenile Crested Caraca- ras, observed later as breeding adults, and their dispersal distances. Year No. Nestlings Marked M F Known Adults Found as Breeders Sex Age When First Found Breeding Distance FROM Natal Area to Breeding Area (km) 1994 14 16 — 1995 23 28 F 3 19.24 pa 4 19.20 1996 28 36 M^ 3 5.84 M 3 6.81 M 3 3.86 M 6 9.08 F 3 16.97 F 3 20.70 1997 9 6 F 4 40.72 Total 74 86 9 Breeding pair. the location where it was found as a breeding adult. We dehne natal dispersal as movement between birthplace and first breeding site (Greenwood 1980, Greenwood and Harvey 1982). Results and Discussion During 1994-97, we banded 160 nestling caracaras: 74 males and 86 females in 55 different breeding areas. Since the 1998-99 breeding season, while conducting regular monitoring of nesting activity in our sample of breeding areas, we have encountered four males and hve females banded as nestlings that were occupying nest sites as breeders (Table 1). Distances between natal areas and breeding sites dif- fered significantly {t = —3.76, P = 0.02) between male (x = 6.40 km ± 1.08 SE, range = 3.86-9.08 km, W = 4) and female caracaras (x = 23.37 km ± 4.38 SE, range = 16,97-40,72 km, N = b). The breeding areas in which we found known males were located only two to three breed- ing areas away from their respective natal areas, based on a mean home-range diameter in Florida of ca. 5 km (J. Morrison unpubl. data). Despite the small sample size, these results corroborate the general pattern of female biased dispersal observed in birds (Greenwood 1980, Johnson and Gaines 1990, Paradis et al. 1998) including many raptors (Newton and Marquiss 1983, Mearns and Newton 1984, Rosenfield and Bielefeldt 1992, Millsap and Bear 1997, Wiklund 1996, Ellsworth and Belthoff 1997, Lehman et al. 2000). Our results also supported that the age at first breed- ing for the Crested Caracaras was 3 yr of age, as was pre- viously suspected (Voous 1955, Layne 1996). Caracaras attain full adult plumage during their fourth year (Layne 1996, J. Morrison pers. observ.), and throughout our study, we rarely observed a breeding caracara in Basic 1 plumage (age 2-3 yr) and never in the juvenile plumage (age 1 yr; Wheeler and Clark 1996). While we cannot entirely rule out caracaras breeding at age 1 or 2, the rarity of breeders in Basic 1 plumage (4.7%, N = 108) observed in our sample of breeding areas combined with our observations of known 3-yr-old caracaras breeding support age at first breeding as 3 yr for Florida’s caraca- ras. Distances we report here likely constitute natal dis- persal for the 3-yr-old individuals. Because we do not know age at first breeding for the two 4-yr-old females and the 6-yr-old male, we are unable to assess whether distances reported for these individuals constitute natal or breeding dispersal. In any case, the new information reported here reveals distances that female and male ca- racaras in Florida travel between their natal site and a breeding site. Explanations proposed for gender-biased, natal dis- persal in birds include reproductive enhancement through mate and/or resource access and inbreeding avoidance (Greenwood 1980, Newton and Marquiss 1983, Pusey 1987, Korpimaki 1988, Johnson and Gaines 1990, Daniels and Walters 2000). Inbreeding avoidance could be an important selective factor for gender-biased dis- persal in this non-migratory, isolated population of ca- racaras. However, interpretation of the observed patterns of dispersal distances reported here is complicated be- cause our annual monitoring efforts were focused on sites of known previous nesting, and we did not search for recruits throughout the study area, so we could have missed other pairs that may have included individuals banded as nestlings. The low encounter rate of banded individuals during annual monitoring efforts could be due to several factors. Mortality rates could be high during the period before hrst breeding, but low encounter rates could also reflect the high survival and site fidelity of adults in this popu- lation ( J. Morrison unpubl. data) , which, combined with limited suitable nesting habitat, may restrict opportuni- ties for recruitment. Additionally, although unlikely, there is a possibility that some juveniles dispersed outside the study area to breed in other areas within Florida or even in other parts of North or Central America. How- ever, no reports of banded caracaras, either recoveries or resightings, from distant populations have been received thus far. Furthermore, data obtained during 1995-2000 using telemetry for 131 juvenile caracaras radio-marked as nestlings within this population suggest that juveniles remain within the species’ current Florida range, at least during the first 3 yr post-fledging (J. Morrison unpubl. data). Unfortunately, no transmitters lasted long enough to provide information on recruitment of radio-marked individuals. Conclusions about dispersal behavior derived from data collected over a finite study area can be biased due to a non-uniform probability of resighting as a function of the distance dispersed (Moore and Dolbeer 1989, Ko- enig et al. 1996). Because we did not search for banded individuals outside the study area, we could have missed finding other recruits. We believe, however, that our sam- ple of breeding areas scattered throughout the study area is representative of the population and, therefore, that the observed difference in mean dispersal distances be- tween males and females, even given the small sample September 2002 Short Communications 205 size, provides evidence for female-biased dispersal in this population of Crested Caracaras. Continued data collection on dispersal is needed for Crested Caracaras in Florida and throughout their geo- graphic range to understand population structure and how these raptors use habitats and respond to landscape change. Our limited observations of dispersal movements in the Florida population may not be representative of the species overall due to broad differences in land use and habitat characteristics in other parts of the caracara’s geographic range. We suggest, however, that the finding of female-biased dispersal in the species probably applies throughout the range, although distances involved prob- ably vary among populations. Although the Crested Ca- racara has not received much conservation attention else- where, recent concern for the species’ status has developed in Mexico (Rivera-Rodriguez and Rodriguez- Estrella 1998) and in parts of Argentina (Goldstein 2000) because of the loss of suitable nesting habitat in those regions as a result of rapid urban growth. To better un- derstand this species’ ecology and response to landscape change throughout its geographic range, additional stud- ies of population dynamics and movement patterns for a number of populations are essential. Resumen. — Como parte de un estudio poblacional a lar- go plazo del Caracara de Florida ( Caracara cheriivay) , dur- ante 1998-2002, encontramos cuatro machos en reprod- uccion y cinco hembras en el mismo estadon, los cuales habian sido anillados en el nido. Nuestras observaciones sostienen que la edad de la primera reproduccion en esta poblacion ocurre a los tres ahos. Las distancias de disper- sion de la natalidad fueron considerablemente mas gran- des para las hembras que para los machos; una hembra fue encontrada reproduciendose en un lugar a 40 Km del area de nacimiento. Estas observaciones sugieren que la dispersion de las hembras en los caracaras de Elorida es similar a la de otras rapaces. Los estudios de movi- mientos individuales y de la dinamica de poblaciones, son esenciales para entender la respuesta de los caracaras a la amplia perdida de habitat y a los cambios de uso de la tierra en Elorida y para el desarrollo de planes de con- servacion ehcientes para esta poblacion aislada y residen- te. [Traduccion de Cesar Marquez] Acknowledgments We sincerely thank the landowners throughout south- central Florida who so generously provided access to their lands so that we could conduct observations in the breeding areas. We also thank J. Arnett, T. Dean, V. Dreitz, J. Hodgson, W. Jess, S. McGehee, L. Phillips, and L. Todd for their excellent assistance in the field. Fund- ing was provided by the Avon Park Air Force Range, the Non-game Wildlife Program of the Florida Fish and Wild- life Conservation Commission, and the South Florida Wa- ter Management District. We gratefully acknowledge the cooperation and logistical support provided by personnel at the MacArthur Agro-Ecology Research Center and Archbold Biological Station. Einally, thanks go to the De- partment of Wildlife Ecology and Conservation of the Institute of Eood and Agricultural Sciences, University of Florida, for providing additional funding and logistic sup- port. This manuscript benefited from reviews and com- ments by M. Goldstein, J. Layne, and J. Walters. This is contribution No. 57 from the MacArthur Agro-Ecology Research Center of Archbold Biological Station. Literature Cited Daniels, S.J. and J.R. Walters. 2000. Inbreeding depres- sion and its effects on natal dispersal in Red-Cockad- ed Woodpeckers. Corador 102:482-491. Ellsworth, E. and J.R. Belthoff. 1997. Sex-biased dis- persal of young Western Screech-Owls (Otus kenmcot- tii) in southwestern Idaho. Pages 155—159 mJ.R. Dun- can, D.H. Johnson, and T.H. Nicholls [Eds.] Proc. Int Symposium on Biol, and Cons, of Owls of the North- ern Hemisphere, Winnipeg, Manitoba, Canada. Goldstein, M.I. 2000. Nest-site characteristics of Crested Caracara in La Pampa, Argentina. J. Raptor Res. 34. 330-333. Greenwood, P.J. 1980. Mating systems, philopatry and dispersal in birds and mammals. Anim. Behav. 28' 1140-1162. and P.H. Harvey. 1982. The natal and breeding dispersal of birds. Ann. Rev. Ecol. Syst. 13:1-21. Howard, W.E. 1960. Innate and environmental dispersal of individual vertebrates. Am. Midi. Nat. 63:152-161. Johnson, M.L. and M.S. Gaines. 1990. Evolution of dis- persal: theoretical models and empirical tests using birds and mammals. Ann. Rev. Ecol. Syst. 21:449-480. Koenig, W.D., D. Van Vuren, and P.N. Hooge. 1996. De- tectability, philopatry, and the distribution of dispersal distances in vertebrates. Trends Ecol. Evol. 11:514—517 Korpimaki, E. 1988. Effects of territory quality on occu- pancy, breeding performance and breeding dispersal in Tengmalm’s Owl./. Anim. Ecol. 57:97-108. Layne J.N. 1996. Crested Caracara. Pages 197-210 mj. Rogers, Jr., H.W. Kale ll, and H. Smith [Eds.]. Rare and Endangered Biota of Florida. Vol. 5. Birds. Univ. Press of Florida, Gainesville, FI, U.S.A. Lehman, R.N., K. Steenhoe, L.B. Carpenter, and M.N Kochert. 2000. Turnover and dispersal of Prairie Fal- cons in southwestern Idaho./. Raptor Res. 34:262-269 Mearns, R. and I. Newton. 1984. Turnover and dispersal in a peregrine Falco peregrinus population. Ibis 126* 347-355. Millsap, B.A. 1989. Final progress report, Crested Cara- cara population survey. Non-Game Wildlife Program, Florida Game and Fresh Water Fish Commission, Tal- lahassee, FL U.S.A. AND C. Bear. 1997. Territory fidelity, mate fidelity, and dispersal in an urban-nesting population of Flor- ida Burrowing Owls. /. Raptor Res. Report 9:91-98. Moore, W.S. and R.A. Dolbeer. 1989. The use of band- ing recovery data to estimate dispersal rates and gene flow in avian species: case studies in the Red-winged Blackbird. Ctmcfor 91:242-253. 206 Short Communications VoL. 36, No. 3 Morrison, J.L, 1996. Crested Caracara {Caracara plan- cus). InK. Poole and F. Gill [Eds.]. The birds of North America, No. 249. The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists’ Union, Washington, DC U.S.A. . 1998. Effects of double brooding on productivity of Crested Caracaras. Auk 115:979-987. . 1999. Breeding biology and productivity of Flor- ida’s Crested Caracaras. Cowrfor 101:505— 517. AND S.R. Humphrey. 2001. Conservation value of private lands for Crested Caracaras in Florida. Conserv. Biol 15:675-684. AND M. Maltbie. 1998. Methods for gender iden- tification of Crested Caracaras./. Raptor Res. 33:128- 133. Newton, I. and M. Marquiss. 1983. Dispersal of Spar- rowhawks between birthplace and breeding places. / Anim. Ecol 52:463-477. Paradis, E., S.R. Baillie, W.J. Sutherland, and R.D. Gregory. 1998. Patterns of natal and breeding dis- persal in birds./. Anim. Ecol 67:518-536. PusEY, A.E. 1987. Sex-biased dispersal and inbreeding avoidance in birds and mammals. Trends Ecol Evol 2: 295-299. Rivera-Rodri'guez, T.B. and R. Rodriguez-Estrella 1998. Breeding biology of the Crested Caracara in the cape region of Baja California, Mexico. / Eield Orni- thol 69:149-159. Rosenfield, R.N. and J. Bielefeldt. 1992. Natal dispersal and inbreeding in the Cooper’s Hawk. Wilson Bull 104:182-184. U.S. Fish and Wildlife Service. 1987. Endangered and threatened wildlife and plants; threatened status for the Florida population of the Audubon’s Crested Ca- racara. Final Rule. Fed. Reg. 52:25229-25231. Voous, K.H. 1955. Birds of the Netherlands Antilles. De Walberg Pers. Curacao, Natuurweten-Schappelijke Werkgroep, Nederlandse, Antillen. Walters, J.R. 2000. Dispersal behavior: an ornithological frontier. Coniior 102:479-481. Wheeler, B.K. and W.S. Clark. 1996. A photographic guide to North American raptors. Academic Press, New York, NY U.S.A. Wiklund, C.G. 1996. Determinants of dispersal in breed- ing Merlins (Ealco columharius) . Ecology 77:1920-1927. Received 13 September 2001; accepted 24 April 2002 / Raptor Res. 36(3) :206-212 © 2002 The Raptor Research Foundation, Inc. Recent Records of Crowned Eagles (Harpyhaliaetus coronates) from Argentina, 1981-2000 M. Isabel Bellocq,^ Patricio Ramirez-Llorens, and Julieta Filloy Departamento de Ciencias Biologicas, FCEN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, Buenos Aires 1428 Argentina Key Words: Crowned Eagle, Harpyhaliaetus coronatus; new records', conservation-, status', Argentina. The Crowned Eagle {Harpyhaliaetus coronatus) is a vul- nerable species whose distribution is limited to south-cen- tral South America (Collar et al. 1992, Garcia-Fernandez et al. 1997). The species has been protected in Argentina since 1954 and is listed as a threatened species in Brazil and Paraguay. The ecology of this large eagle is poorly known. It feeds on a variety of vertebrates including snakes (e.g., Waglerophis merremi) ,hivds,, skunks {Conepatus spp.), armadillos (Dasypodidae), and weasels (Collar et al 1992). The nest of the Crowned Eagle consists of a large platform placed in trees where one egg is laid (De la Pena 1992, Bellocq et al. 1998). Naturally low popu- ^ E-mail address: bellocq@bg.fcen.uba.ar lation numbers and habitat fragmentation have been rec- ognized as primary contributors to the eagle’s current status (Collar et al. 1992). Previous studies on habitat use by this eagle identified the potential negative effects of continuing afforestation (Bellocq et al. 1998). Over 60% of the Crowned Eagle records are from Argentina, where it occurs primarily in shrublands, savannas, and semi- open woodlands (Collar et al. 1992, Bellocq et al. 1998, Gonnet and Blendinger 1998). Crowned Eagles were also reported recently in subtropical rainforests (Chebez et al. 1998, Gonnet and Blendinger 1998). Here, we report new records of Crowned Eagles and integrate them with the previous information on this species from Argentina for 1981-2000. Methods Road surveys for raptors were conducted in the north- west portion of Santa Fe province, north-central Argen- September 2002 Short Communications 207 72® 68® 64® 60® 56® ki 52® Figure 1. Observation records of Crowned Eagles (Harpyhaliaetus coronatus) from Argentina during 1981—2000 (see Appendix for details on records). Zones A (northwestern Santa Fe), B (northeastern Mendoza and northern San Luis) , and C (central La Pampa) are areas with a high number of records. tina (west of Zone A, Fig. 1). The survey was conducted along 210 km of road, driving north at a speed of 60-80 km/hr during 21 (from Nueva Italia to Tostado) and 22 November 2000 (north of Tostado). Raptor counts were made by one observer (who was not driving) while in transit, and occasional stops were made for identification and counting of individuals in groups. We compiled information and identified locations for records of Crowned Eagles from Argentina for the period 1981-2000. Gonnet and Blendinger (1998) compiled most records from 1987-97. For each record, we ob- tained the following information (when available): loca- tion, geographic coordinates, province, date, number of individuals, and source. When not provided in the source, we obtained geographic coordinates at the Insti- tuto Geografico Militar (IGM) or contacted observers to obtain complete information. Reference numbers were basically assigned for records from north to south. Results and Discussion A total of 343 individueil raptors was recorded during the road survey in 2000; these included 161 Swainson’s Hawks (Buteo swainsoni), 114 Crested Caracaras (Polyborus plancus), 56 Black Vultures (Coragyps atratus), four Crowned Eagles {Harpyhaliaetus coronatus), four Black- chested Buzzard-Eagles {Geranoaetus melanoleucus) , two Chimango Caracaras {Milvago chimango), one Roadside Hawk {Buteo magnirostris) , and one Snail Kite {Rostrhamus sociabilis ) . We observed four Crowned Eagles during the raptor 208 Short Communications VoL. 36, No. 3 survey and one additional individual while traveling around the area. We were able to identify distinguishing plumage features of each juvenile indicating that we ob- served different individuals. All individuals were seen be- tween 29-30°S and 61-62°W, where the land is used pri- marily for ranching. On 20 November 2000, an adult and a juvenile eagle were observed at Hwy 2, 20.5 km north of Nueva Italia (29°47'S, 61°32'W; record number 32 in Fig. 1). The adult was perched on an electric pole and the juvenile was on the ground holding a snake {Philodryas patagon- lensis) in its talons. The surronnding habitat had two veg- etation strata, trees and grasses, where Geoffroea decorticans (height about 6 m) dominated the canopy covering 40- 60% of the ground surface. On 20 November 2000, a juvenile was seen perched on a power pole at Hwy 2, 37 km south of Tostado (29°26'S, 61°43'W; record number 27 in Fig. 1). We were able to approach the base of the pole without flushing this eagle. The habitat was a Prosopis savanna with sparse G. decorti- cans. On 21 November 2000, we observed ajnvenile perched on a Prosopis tree (height about 6 m), on Hwy 9.5, 21 km north of the intersection with Hwy 2 (29°07'S, 61°43'W; record number 21 in Fig. 1). The eagle was perched in a pasture with isolated Prosopis where cattle grazed. Sur- rounding fields were cultivated with sunflower. On 21 November 2000, we recorded a juvenile eagle while traveling around the area. The eagle was perched on a fence pole on Hwy 13, 18.5 km south of the inter- section between Hwys 13 and 98 (29°26'S, 61°03'W; re- cord number 26 in Fig. 1). The habitat was a pasture where Spartina spp. was the most common grass (60-80% cover) . We compiled 72 records from Argentina for 1981-2000 (record numbers in Appendix correspond to location numbers in Fig. 1 ) . The three zones with a high freqnen- cy of records (Fig. 1) have a semiarid climate, and each include a portion of two phytogeographic regions (fol- lowing Cabrera 1971), and the ecotone between them. Zone A is located in the northwestern portion of Santa Fe province. In the northern part of this zone (Chaqueha region, de las Sabanas District) , vegetation types include savannas of Elionurus muticus in the upper areas and Spar- Lina argentinensis in the lower areas. In the southern part of zone A (El Espinal region, del Algarrobo District), close to open woodlands, Prosopis spp. and G. decorticans dominate the landscape. The area is affected by affores- tation and the land is primarily used for ranching. G. decorticans forests occur in areas disturbed by ranching. Zone B comprises northeastern Mendoza and northern San Luis provinces. In northern San Luis (Chaqueha re- gion, Serrano District), the original woodlands of Schin- opsis spp. were replaced by shrublands with isolated woodlots of Prosopis spp. In eastern Mendoza (Monte re- gion) , the primary vegetation type is a shrubland domi- nated by Larrea spp. Other shrub species include Monttea aphylla, Bougainvillea spinosa, Prosopis alpataco, and Chu- quiraga erinacea. Zone C is located in central La Pampa province. In the eastern part of this zone (El Espinal re- gion, del Calden District), the natural xerophic forest dominated by Prosopis caldenia has been modified as a result of afforestation followed by ranching. Cnrrently, this zone consists of shrublands (mostly Larrea spp.) with isolated P. caldenia or small woodlots. Some common ac- companying shrubs are Lycium chilense, Prosopis flexuosa, Condalia microphylla, G. erinacea, and G. decorticans. The western part of zone C is within the Monte phytogeo- graphic region described above. Of the 72 records found from Argentina for 1981- 2000, approximately 23%, 21%, and 19% are from zones A, B, and C, respectively (Eig. 1). Gonnetand Blendinger (1998) suggested zones A and B as potential areas to in- tensify research and conservation efforts. Zone A, how- ever, has some advantages over zones B and C. First, zone A is located near the central portion of the species’ range compared to other zones. Second, many of the records from zones B (40%) and C (57%) are from or around natural reserves, whereas no record from zone A is from natural reserves. Eagles are more likely to be seen in nat- ural reserves due to increased sampling efforts and re- duced habitat alteration and hunting pressure (Gonnet and Blendinger 1998). The conservation of large-bodied, low-density, upper-trophic-level species often requires suitable habitat beyond the size of existing natural re- serves (Meffe and Carroll 1997). Third, our results might indicate a relatively high density of eagles in zone A, con- sidering both the naturally low population numbers and the results of previous surveys. The available information from previons surveys (Travaini et al. 1995, Bellocq et al 1998, Contreras and Justo 1998, Gonnet and Blendinger 1998) suggests that sighting hve Crowned Eagles in 2 days of observations is unusually high. In summary, we reported four new records of Crowned Eagles (including five individuals) , compiled and provided details of records in Argentina for 1981-2000, and iden- tified three zones with high frequency of recent records Based on this study, we suggest the following priorities for research and conservation of the Crowned Eagle: (1) com- plete snrveys along the Espinal phytogeographic region, (2) identify variables associated with high frequencies of eagle sightings at larger geographical scales (e.g., land- scape), and (3) conduct studies on reproductive success and mortality to identify viable populations. Resumen. — El aguila coronada {Harpyhaiiaetus coronatus) es una especie vulnerable y rara de ver. Se observaron cuatro ejemplares durante un relevamiento de rapaces por carretera a lo largo de 210 km, y un individuo adi- cional cuando se recorria el area en el centro-norte de Argentina (Santa Ee). Se compilaron los registros de Ar- gentina para el perfodo 1981-2000 y se identificaron tres zonas de alta frecuencia de registros recientes. La zona ubicada en el noroeste de la provincia de Santa Ee parece September 2002 Short Communications 209 ser la mas apropiada para intensificar investigacion y ac- ciones de conservacion, debido a su posicion relativa- mente central dentro de los Kmites de distribucion de la especie y su alta frecuencia de registros recientes afuera de reservas naturales. [Traduccion de los autores] Acknowi .edgments We thank Aves Argentinas for helping with literature search and G. Carrizo, from the Museo Argentino de Ciencias Naturales Bernardino Rivadavia, for identifying the snake. J.M. Gonnet and two anonymous reviewers provided comments that improved the manuscript. The research was supported by the Gonsejo Nacional de In- vestigaciones Cientificas y Tecnicas of Argentina and the Lincoln Park Zoo. Literature Cited Bellocq,, M.L, S.M. Bonaventura, F.N. Marcelino, and M. Sabatini. 1998. Habitat use by Crowned Eagles {Harpyhaliaetus coronatus) in the southern limit of the species’ range./. Raptor Res. 32:312-314. Cabrera, A.L. 1971. Fitogeografia de la Republica Argen- tina. Bol. Soc. Argent. Bot.\ 14 (1-2). Chebez, J.C., N.R. Rey, M. Babarskas, and A.G. Di Gi- acomo. 1998. Las aves de los Parques Nacionales de la Argentina. Administracion de Parques Nacionales y Asociacion Ornitologica del Plata. Monografia Es- pecial, L.O.L.A. No. 12, Buenos Aires, Argentina. Collar, N.J., L.P. Gonzaga, N. Krabbe, A. Madrono, L.G. Naraujo, T.A. Parker, and D.C. Wege. 1992. Threatened birds of tbe Americas. The ICBP/IUCN red data book. Smithsonian Institution Press, Wash- ington, DC U.S.A. Contreras, J.R. and E.R. Justo. 1998. Abundanciay den- sidad relativa de rapaces (Aves: Accipitridae y Falcon- idae) en el noreste de la provincia de La Pampa. N6- tulas Faumsticas 92:1—3. De La Pena, M.R. 1992. Guia de aves argentinas. Editorial L.O.L.A. Buenos Aires, Argentina. . 1999. Aves Argentinas, Lista y Distribucion. Edi- torial L.O.L.A., Buenos Aires, Argentina. Dei.HEY, R. 1992. Algunas aves nuevas o poco conocidas para la region de Bahia Blanca. Nuestras Aves 27 31- 32. De Lucca, E.R. 1992. El aguila coronada Harpyhaliaetus coronatus en San Juan. Nuestras Aves 26:25. . 1993. El aguila coronada. Nuestras Aves Di Giacomo, A. 1996. Reserva ecologica El Bagual, un ejemplo concreto. Nuestras Aves 34:1-4. GarcIa-Fernandez, J.J., R.A. Ojeda, R.M. Fraga, G.B. DIaz, and R.J. Baiglin. 1997. Libro rojo de mamiferos y aves amenazados de la Argentina. F.U.C.E.MA, A.P.N., Buenos Aires, Argentina. Gil, G., E. Haene, and J.C. Chebez. 1995. Notas sobre la avifauna de Sierra de las Quijadas. Nuestras Aves 31. 26-28. Gonnet, J.M. and P.G. Blendinger, 1998. Nuevos regis- tros de distribucion del aguila coronada (Harpyhahae- tus coronalu.s) en el oeste de Argentina. Hornero 15.39— 42. Kaspar, J., V. Deliiey, and M. Carrete. 1999. Aves nuevas o poco conocidas para el sudoeste de la provincia de Buenos Aires, Argentina. Nuestras Aves 40:11-12. Meefe, G.K. and C.D. Carroll. 1997. Conservation re- serves in heterogeneous landscapes. Pages 305-343 in G.K. Meffe and C.R. Carroll [Eds.], Principles of con- servation biology. Sinauer, MA U.S.A. Nellar-Romanelia, M.M. 1993. Aves de la provincia de San Luis: lista y distribucion. Museo Privado de Cien- cias Naturales e Investigaciones Ornitologicas Guiller- mo E. Hudson, San Luis, Argentina. SAI.VADOR, S.A. AND P.G. Eroles. 1994. Notas sobre aves de Santiago del Estero. Nuestras Aves 30:24-25. Travaini, a., a. Rodriguez, O. Cebai.los, J.A. Donazar, AND F. Hiraldo. 1995. Roadside raptor surveys in cen- tral Argentina. Hornero 14:64—66. Received 5 March 2001; accepted 14 May 2002 Appendix The record number, number of sighted indmduals, locality, geographic coordinates, and source of observation records of Crowned Eagles from Argentina for 1981-2000. 210 Short Communications VoL. 36, No. 3 w u 'A D O c/3 U W o o u Q 1 ^ u o o ^ oz 00 00 00 O 05 cji 05 075 05 u 5m 5m D U D bo be be d d d .MM— S .M— N X 00 05 00 (35 CM CM CM CM d d d (05 (05 .M— S (05 (05 (05 <05 D V ■i-f -UJ P-J N N D D D D V D D 5-< 5m U U c, C C X X , 1 d d d 'D 'V o 0 0 Md X D o o o o O O O U U Q U U u u on 05 f>5l o U 00 05 05 Vh OJ be cT ^ 05 - — . fl 05 CO o cf g S "O CJ u 0 hJ rt 15 O U 1) S 0 o O 1> ^ O CO OO 50 50) 50 o o o o ^ ^ ^ ^ 50 O iD CD cd O lO 50 O 'Ch CO GO ^ o o o o C^f GO GO GO Of C^f 1> 50 50 'Ch 't' 05 O) 5j 0 50 50 > o CD CD 00 ^ GO 00 GO O Of Of o o o o f> CO 00 00 Df Of Of Of o a c/^ *!T2 '^75 ? cb u C d Ch d z d cci c/3 cG d -d A 'rt U ai g CO : d Sf— I 3 o O o f/2 0 Sm 0 Pm Sm D Sm D Sm D a cd 0 5^ CJ tin c/5 pp c^ PP d pp 0 d be G CJ p— ' !/5 tlj p-j C "d "d ij M J X X -d -d w » CJ o o o O W T! i/T rt I be be be 0 u G G G c/i u Pp n 0 a u s n u b C3 C/3 Oi ai ■.—I '^5 D^ nj rd -y o d d d ci c/3 C/3 o"' o'' a Gh o o O U a; ai U pi d C/^ '' ttd O ^ U o biD 'o i-H D cn D .2 u ■d S id cG CO ^ £i^ U oj u a ■f— I u o 4-t i/5 o; ^ ai CO u S 0 C T s ^ l> o d 00 Of <0 ^ I ^ \ CD O 1> CO or Of 03 D d 03 d 03 D d 03 d GO G5 05 GO 2) Z D d d 05 00 05 d3 C05 Pn S-i D Of 05 Of Of CM 05 05 05 05 O) 05 Of CM CM CM 05 05 05 05 05 C05 05 05 Of CM CM Of 05 05 05 05 05 05 CO) t05 CG u D Cb 'O w 0 > >. 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On 12 February 1996, one adult peregrine flew in front of the cliff. It had a broad mous- tache and was dark on the upperside and rusty below On 6-7 April 2001, an adult male peregrine was observed for several hours, perched and flying along the cliff. It had a very broad moustache, almost a dark facial mask, and huffish underparts. On both days, the “creaking call” (Ratcliffe 1993) was heard, indicating the presence of a second peregrine, presumably the female, which was not seen. The cliff had extensive whitewash in several places, suggesting prolonged occupancy. It overlooks the Colca river in a rich agricultural valley and thus appears a classic peregrine haunt. (6) City of Arequipa (16°24'S, 7rS3'W): 12 April 2001, one female seen stooping in the city center (elevation 2300 m) . (7) Machu Picchu (13°08'S, 72°34'W): 17 April 2001, September 2002 Short Communications 215 I?! / y \ Ecuador A 7 / ; / Cofdmbia ^ ! \ ( N I V- ft »«■■■. A •nIJ Chiclayox t / r> Brazil N ) : Lima\ 8-^ A •A \ ’■ \. ■* \ - % 'A 1 0 \ 0 130 ^’ Cusco \ VA., > ■ i\ - i.‘ \ 4 L-, JTi • VU: \ '2l1 • Confirmed breedifrg 0 Pair • Single bird 500 km □ Arequipa 5 Chile] Figure 1. Distribution of the Peregrine Falcon {Falco peregrinus) in Peru. The locations of observations referring to known or suspected breeding pairs are shown. The dark shaded area marks Andean regions above 2000 m elevation To its west is the coastal strip, and to its east, the Amazon forest. Numbers mark the locations in order of their appearance in the text: 1 (Yauli; Morrison 1939), 2 (San Ramon; Gochfeld 1977), 3 (La Merced; Gochfeld 1977), 4 (Tacna; Ellis and Glinski 1980), 5-7 (Olmos; Schoonmaker et al. 1985), 8 (Lima), 9 (Lagunillas) , 10 (Laguna Grande), 11 (Canon de Colca), 12 (Machu Picchu), 13 (Cusco), 14 (Calca-Lamay) , 15 (Chilca-Guayllabamba; D. Michelat, pers. comm.), 16 (Pisac; D. Michelat pers. comm.), 17 (Ca- banaconde-Tapay; F. Schmitt, pers. comm.), 18-23 (Lima and surroundings; O. Beingolea, pers. comm.). one adult pair with the tiercel attacking an intruding im- mature tiercel, at the east-facing cliff of Huayna Picchu, the little sugar-loaf mountain overlooking that world-fa- mous ancient Inca city at an elevation of ca. 2400 m. The pair had broad moustaches and generally dark plumage (including strong markings below), but no pronounced buffness on the underside. They frequently gave the wail- ing and the creaking calls when together, and the tiercel the caching call (Ratcliffe 1993) when chasing away the intruder. The two adults were clearly paired, engaged in courtship flights and perched on the cliff, although not close together. (8) Inca site of Sacsayhuaman at Cusco (13°29'S, 7l°57'W): 18 April 2001, one adult pair was seen at an elevation of ca. 3400 m, soaring at this location devoid of any cliffs. They were in a “playful mood” and repeat- edly made mock attacks on each other. Both birds ap- peared fairly dark on the underside. 216 Short Communications VoL. 36, No. 3 (9) Valle Sagrado between Calca and Lamay (13°21'S, 7l°54'W): 19 April 2001, one adult pair seen at the in- land cliff at kilometer post 48 on the right side of the river valley at an elevation of ca. 3000 m. On 20 April 2001, one adult bird perched in the same cliff. On 16 January 2002, I saw one adult hunting and then perched m the cliff. This site is located in the broad valley of the Urubamba river, which has rich agricultural land at the bottom and excellent cliffs available almost continuously for many kilometers. The valley here looks like prime peregrine habitat. (10) Valle Sagrado between Ollantaytambo and Pachar (13°18'S, 72°12'W): 18 February 1996, 1 caught a glimpse of a large falcon stooping east of the village of Ollantay- tambo at an elevation of ca. 2800 m. On 21-22 April 2001, however, during 5 hr of observation, no peregrines were observed. On 14 January 2002, during 1 hr nothing seen either. The Urubamba valley at this site looks ex- cellent for nesting peregrines. It is only slightly narrower than upriver at Calca, and again with abundant huge cliffs. Discussion It is well-known that the important migrant popula- tions of F. p. tundrius and anatum from the tundra and taiga in North America distribute themselves throughout most Latin America during the northern winter (see Fig. 1 in Henny et al. 1996 and Fuller et al. 1998). Most of my February-May observations were made at a time when the northern migrants may overlap with nesting activities of local birds. Therefore, an obvious question is whether the reported observations concern migrants or instead locally breeding birds. Based on the plumage and behavior criteria men- tioned, some birds observed at the Paracas National Park and at Chala may have been northern migrants. In the austral summer, the greater Lima area has a relatively high density of peregrines of both migrant and local or- igin (O. Beingolea pers. comm.). Thus, nothing can be said of the birds observed in Lima and also of that in Arequipa, because not enough details were seen. Based on date, behavior and plumage, the pairs at La- gunillas beach. Laguna Grande, Machu Picchu, Calca, and the repeated observations in the Canon de Colca may have been locally-breeding birds. The pair at Cusco were probably not migrants either. These observations, thus, suggest up to six new peregrine pairs in Peru. This supports the suggestion by McNutt et al. (1988) that breeding peregrines are probably more widespread in the central Andes than hitherto recorded. Further support for this hypothesis comes from recent sightings by other observers outside the period when northern migrants are present. In August 1995, D. Mich- elat (pers. comm.) saw single peregrines in the Canon de Colca as well as at two widely separated sites in the Valle Sagrado; near Pisac and downriver from Ollantay- tambo, between Chilca and Guayllabamba. On 27 July 2001, F. Schmitt (pers. comm.) watched a pair in a cliff overlooking the Rio Colca on its left side, between the villages of Tapay and Cabanaconde. The pair was calling frequently and perched on a heavily white-washed ledge that looked like an eyrie. This .site is some 10 km down- river from the site where I watched peregrines in that valley, so this observation presumably indicated a sepa- rate territory rather than a very distant alternate nesting cliff. According to G. Engblom (pers. comm.) the Machu Picchu pair was already confirmed in 1999. Interestingly, S. Lovis (pers. comm.) thought he heard a peregrine call- ing in the background of a television documentary on Machu Picchu in the early 1990s! Finally, O. Beingolea (pers. comm.) found three cliff-nesting peregrine pairs close to the city of Lima in 1993 and by 2001 had located six nesting pairs, one of which was nesting on a building in urban lima (O. Beingolea and G. White, unpubl data) . Collectively, these observations and the literature re- cords mentioned above suggest the presence of at least 19-23 peregrine pairs in Peru (Fig. 1). Ten are located in the western foothills of the Andes (including Lima city), two on the coast, five to seven in the Andean high- lands, and three to four on the eastern slopes of the An- des. These proportions may not be representative of the true distribution of breeding peregrines in Peru; instead they may reflect the accessibility of and ornithologists’ activity in these regions, especially in the lama area (O. Beingolea) and in northern Peru (Schoonmaker et al 1985). Breeding pairs have been suspected at very high elevations; 3250 m in the Cafion de Colca and possibly at .similar elevations near Cusco (this study) and 3300 m at Yauli (Morri.son 1939). These findings raise the usual question of whether this greater frequency of reports reflects a real population increase or just additional observation intensity. Al- though it may be hard to imagine that the pairs at Machu Picchu and in Lima were overlooked for a long period, at present, nothing conclusive can be said. The observa- tions reported here greatly increase the known geograph- ic range of the peregrine in South America. Thus, I urge others to watch out for the peregrine in the countries of the central/northern Andes. RE.SUMEN. — Entre febrero y mayo 1996 y 2001 y en enero 2002, observe 28 halcones peregrinos {Falco peregrinus) en un total de nueve sitios en el centro y el sur del Peru Ginco individuos fueron observados en lima, 12 en o cerca de acantilados maritimos de tres sitios costeros, ocho en acantilados en tres sitios del interior del pais Tres individuos fueron observados en el interior del pais lejos de acantilados. Aunque algunos de esos halcones podrian habcr sido individuos invernantes desde Nortea- merica, detalles del plumaje y del comportamiento, sug- ieren la presencia de parejas anidando en dos sitios cos- teros (al sur de Pisco) y en el interior del pais (Canon de Colca, Machu Picchu, Calca y cerca de Cusco). Ade- September 2002 Short Communications 217 mas, parejas anidando, seguras o probables, recien ban sido descubiertas por otros ornitologos en siete sitios mas. Estas observaciones, junto a otras anteriormente mencionadas en la literatura, sugieren al menos 19 pa- rejas de halcones peregrinos en el Peru. Esta especie podria estar mas difundida en los paises de los Andes centrales de lo que ha sido observado hasta ahora. [Traduccion de Maria Teresa Chu] Acknowledgments I would like to thank Oscar Beingolea and Jose Anto- nio Otero for sharing with me some of their extensive experience on Peruvian peregrines. Oscar, Dominique Michelat, Fabrice Schmitt, Gunnar Engblom, and Simon Lovis communicated their peregrine observations to me. Christophe Berney and Kinard Boone prepared the dis- tribution map. David Parish, David Ellis, Benedikt Schmidt, James Bednarz, David Whitacre, Richard Nel- son, and an anonymous referee made comments that im- proved the paper. Maria Teresa Chu and David Whitacre helped with the Spanish translation. I thank Susana Mu- noz Lopez for help in the field. I also thank NASA-God- dard SEC for funding publication of this note. Literature Cited Ambrose, R.E. and K.E. Riddle. 1988. Population dis- persal, turnover, and migration of Alaska peregrines. Pages 677-684 in T.J. Cade, J.H. Enderson, C.G. The- lander, and C.M. MTiite [Eds.]. Peregrine Falcon pop- ulations. Their management and recovery. The Per- egrine Fund, Inc., Boise, ID U.S.A. Cade, T.J. 1982. The falcons of the world. Collins, Lon- don U.K. , J.H. Enderson, C.G. Thelander, and C.M. White [Eds.]. 1988. Peregrine Falcon populations. Their management and recovery. The Peregrine Fund, Inc., Boise, ID U.S.A. Ellis, D.H. 1985. The Austral Peregrine Falcon: color var- iation, productivity, and pesticides. Natl. Geogr. Res. 1: 388-394. and R,L. Glinski, 1980. Some unusual records for the Peregrine and Pallid Falcons in South America. Condor 82:350-351. and C. Peres G. 1983. The Pallid Falcon Falco krey- enborgi is a color phase of the Austral Peregrine Falcon {Falco peregrinus cassini). Auk 100:269-271. Fuller, M.R., W.S. Seegar, and L.S. Schueck. 1998 Routes and travel rates of migrating Peregrine Fal- cons Falco peregrinus and Swainson’s Hawks Buteo swainsoni in the western hemisphere. /. Avian Biol. 29‘ 433-440. CocHFELD, M. 1977. Peregrine Falcon sightings in east- ern Peru. Condor 79:391-392. Henny, C.J., W.S. Seegar, and TL. Maechtle. 1996. DDE decreases in plasma of spring migrant Peregrine Fal- cons, 1978-1994./ Wildl. Manage. 60:342-349. Hilgert, N. 1988. Aspects of breeding and feeding be- havior of Peregrine Falcons in Guayllabamba, Ecua- dor. Pages 749—755 in T.J. Cade, J.H. Enderson, C.G Thelander, and C.M. White [Eds.]. Peregrine Falcon populations. Their management and recovery. The Peregrine Fund, Inc., Boise, ID U.S.A. Jenny, J.P., F. Ortiz, and M.D. Arnold. 1981. First nest- ing record of the Peregrine Falcon in Ecuador. Condor 83:387. McNutt, J.W., D.H. Ellis, C. Peres G., T.B. Roundy, W.G. Vasina, and C.M. White. 1988. Distribution and status of the Peregrine Falcon in South America. Pag- es 237-249 in T.J. Cade, J.H. Enderson, C.G. Thelan- der, and C.M. White [Eds.]. Peregrine Falcon popu- lations. Their management and recovery. The Peregrine Fund, Inc., Boise, ID U.S.A. Morrison, A. 1939. The birds of the department of Huancavelica. Ibis 81:453-486. Ratcliffe, D.A. 1993. The Peregrine Falcon, 2nd Ed. T & A.D. Poyser, London, U.K. Schoonmaker, P.K., M.P Wallace, and S.A. Temple 1985. Migrant and breeding Peregrine Falcons m northwestern Peru. Condor 87:423-424. White, C.M. 1968. Diagnosis and relationships of the North American tundra-inhabiting Peregrine Falcons Auk 85:179-191. AND D.A. Boyce. 1988. An overview of Peregrine Falcon subspecies. Pages 789-810 in T.J, Cade, J H, Enderson, C.G, Thelander, and C.M. White [Eds]. Peregrine Falcon populations. Their management and recovery. The Peregrine Fund, Inc., Boise, ID LT.S.A. Received 16 October 2001; accepted 26 April 2002 J Raptor Res. 36(3):218-219 © 2002 The Raptor Research Foundation, Inc. DNA Polymorphisms in Boreal Owls {Aegolius funereus) Janne Beheim Department of Animal Science, Agricultural University of Norway, P.O. Box 5025, 1432 As-NLH, Norway Katrine Eldegard Department of Biology and Nature Conservation, Agricultural University of Norway, RO. Box 5014, 1 432 As-NLH, Norway GRO BJ0RNSTAD Department of Morphology, Genetics and Aquatic Biology, Norwegian College of Veterinary Medicine, P.O. Box 8146 Dep., 0033 Oslo, Norway Mats Isaksson Department of Genetics, Uppsala University, Box 7003, 750 07 Uppsala, Sweden Geir Sonerud Department of Biology and Nature Conservation, Agricultural University of Norway, P.O. Box 5014, 1432 As-NLH, Norway Olav Heie Dr0bak Medical Center, Storgaten 18, 1440 Dr0bak, Norway Helge Klungland^ o Department of Animal Science, Agricultural University of Norway, P.O. Box 5025, 1432 As-NLH, Norway Key Words: Boreal Owl, Tengmalm’s Owl; Aegolius funer- eus; microsatellite; DNA polymorphisms; variability. Molecular analyses of polymorphic DNA-fragments are widely used in phylogenetic studies to recognize individuals, to evaluate mating strategies, and to study genetic diversity (Lawless et al. 1997, Primmer and Ellegren 1998) . A limiting factor in studies that depend on species-specific variation is the number of available markers. Due to the conservational nature of DNA across species, polymorphic regions that are localized in one species will often be of great use in a num- ber of related species. This is also the case for microsatel- lites, which are often localized in less conserved areas (Chambers and MacAvoy 2000). The main focus of this work was to establish DNA polymorphism in the Boreal Owl (Aegolius Junereus funereus) that would be useful for testing patei nity, inbreeding, and population genetics. Microsatel- lites, characterized by short, tandemly-repcated, and highly- polymorphic sequences, were chosen for the analysis. These markers have previously been used for cross-species ampli- fication in birds (Primmer et al. 1996), and in several other ' Corresponding author’s present address: Department of Laboratory Medicine, Faculty of Medicine, Norwegian University of Science and Technology, St. Olavus Hospi- tal, Morfologibygget, 7006 Trondheim, Norway; e-mail address: helge.klungland@medisin.ntnu.no species. Although microsatellites are highly polymorphic (varying number of tandemly-repeated motifs), sequences flanking the microsatellite are still conserved enough to be present across related species, and are used for primer bind- ing. As expected, a negative relationship between microsat- ellite performance and evolutionary distance has been ob- served (Primmer et al. 1996). Methods Blood samples were collected from 44 unrelated free- ranging adult Boreal Owls (Tengmalm’s Owl) nesting in Hedmark County, Norway (ca. 61°N, 11°E) in 1998. Natal as well as female breeding dispersal is extensive in the Boreal Owl, causing genetic swamping over large areas (Sonerud et al. 1988). DNA was isolated following stan- dard protocols (Seutin et al. 1991, Krokene et al. 1996) Amplification of microsatellites in Boreal Owl (Table 1) was based on sequences obtained from the Eurasian Ea- gle-Owl (Bubo bubo; Isaksson and Tegelstrom 2002) Among the microsatellites used in this study Bblll and Bbl26 are GA repeats, whereas, the remaining satellites are CA repeats. Reactions were carried out in 10 gl con- taining 50 ng of genomic DNA, 0.5 U Taq polymerase, enclosed buffer (Perkin Elmer), 2.5 pmol of each primer and 0.2 mM of each dNTP. Genomic DNA was denatured for 3 min at 94°C prior to amplification. The polymerase chain reaction (PCR-amplification) was run for 35 cycles at 94°C (denaturation) for 15 sec, annealing for 15 sec, and elongation at 72°C for 30 sec. Annealing tempera- tures varied from 45°C (Bb42) to 48°C (BblOO, BblOl, 218 September 2002 Short Communications 219 Table 1. Primer sequences (5 '-3') for amplification of Boreal Owl microsatellites. All forward primers (F = for- ward; R = reverse) were fluorescent labelled. Markers Bb42, BblOO, BblOl, Bblll, Bbl26, BblSl, and Bbl45 can be found in Isaksson and Tegelstrom (2002). Marker Primer Sequences Bb20 F Bb20 R Bbl20 F Bbl20 R Bbl34 F Bbl34 R GTGGTGGCACGGCTTGT TGTCAAGAGGAAGCATAAAATACAT TAATGGTGCTGCTGGTGGAAG CATGTGTAGGTGTGGGAGAGAA TTTCTCCACGCTTCCTTTTCATA AGAAGAATGGCTGGCAAGACTC and Bbl45) to 50°C (Bblll and Bbl34) and 52°C (Bbl26). Successful amplification of Bb20, Bbl20, and Bbl31 was not obtained at any annealing temperatures. Microsatellites were analyzed on an ABI 373 sequencer. Results and Discussion Of the ten primer pairs characterized in eagle-owls, sev- en successfully amplified DNA from Boreal Owl (Table 2). Five of these were polymorphic in Boreal Owl, where- Table 2. Length of alleles, allele frequencies and het- erozygosity among 44 unrelated Boreal Owls for seven microsatellites. Microsatellite markers Bb20, Bbl20 and Bbl31 did not amplify DNA successfully from Boreal Owl. Micro- satellite Marker Allele Lengths Allele Frequencies Observed Hetero- zygosity Bb42 304 bp 1.000 0 BblOO 296 bp 0.761 0.30 298 bp 0.239 - BblOl 185 bp 0.477 0.57 187 bp 0.034 189 bp 0.034 191 bp 0.455 Bblll 201 bp 0.023 0.61 203 bp 0.011 205 bp 0.080 207 bp 0.625 209 bp 0.136 211 bp 0.080 213 bp 0.045 Bbl26 185 bp 0.989 0.02 187 bp 0.011 Bbl34 144 bp 1.000 0 Bbl45 242 bp 0.898 0.18 256 bp 0.102 as, the remaining two were monomorphic within the in- dividuals tested in our analysis. Because Boreal Owls and eagle-owls are among the most distantly related species within the Strigidae family (Mindell et al. 1997), these microsatellites may be of potential use in most species within this family. Our findings could therefore be of great importance for the analysis of population genetics, as well as for parental testing in a wide variety of species within the Strigidae family. Resumen. — Hemos utilizado los pares de indicadores con base en secuencias del gran buho euroasiatico con el fin de ampliar exitosamente siete microsatelites de loci en el buho boreal {Aegolius funereus funereus) , de los cuales cm- co fueron polimorfos. El numero de alelos por locus var- iaron entre dos a siete. La conservacion de los microsa- telites de loci entre el buho boreal y el gran buho euroasiatico indica que las secuencias del gran buho pue- den ser utiles en estudios moleculares para la mayoria de especies de la familia strigidae. [Traduccion de Cesar Marquez] Literature Cited Chambers, G.K. and E.S. MacAvoy. 2000. Microsatellites- consensus and controversy. Comp. Biochem. Physiol 126:455-476. Isaksson, M. and H. Tegelstrom. 2002. Isolation and characterization of polymorphic microsatellite mark- ers in a captive population of the eagle-owl, Bubo bubo, used for supportive breeding. Mol. Ecol. Notes '2.\9\-9?>. Krokene, C., K. Anthonisen, J.T. Lifjeld, and T. Amundsen. 1996. Paternity and paternity assurance behaviour in the Blue throat. Lusdnia s. svedca. Anim. Behav. 52:405-417. Lawless, S.H., G. Ritchison, P.H. Klatt, and D.F. West- neat. 1997. The mating strategies of Eastern Screech- Owls: a genetic analysis. 99:213-217. Mindei l, D.R, M.D. Sorenson, C.J. Huddleston, H.C. Mi- randa, Jr., A. Knight, S.J. Sawchuk, and T. Yuri. 1997 Phylogenetic relationships among and within select avi- an orders based on mitochondrial DNA. Pages 213-247 in D.P. Mindell [Ed.], Avian molecular evolution and systematics. Academic Press, London, U.K. Primmer, C.R. and H. Ellegren. 1998. Patterns of mo- lecular evolution in avian microsatellites. Mol. Btol. Evol. 15:997-1008. , A.P. Moller, and H. Ellegren. 1996. A wide- range survey of cross-species microsatellite amplifica- tion in birds. Mol. Ecol. 5:365—378. Seutin, G., B.N. White, and P.T. Boag. 1991. Preserva- tion of avian blood and tissue samples for DNA anal- ysis. Can. J. Zool. 69:82-90. Sonerud, G.A., R. SoLHEiM, and K. Prestrud. 1988. Dis- persal of Tengmalm’s Owl Aegolius funereus in relation to prey availability and nesting success. Ornis Scand 19:175-181. Received 30 August 2001; accepted 20 April 2002 J. Raptor Res. 36(3):220-224 © 2002 The Raptor Research Foundation, Inc. POST-FLEDGING MOVEMENTS AND FORAGING HABITATS OF IMMATURE WHITE-TAILED SeA EAGLES IN THE Nemuro Region, Hokkaido, Japan Saiko Shiraki* Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, 060 0810, Japan Key Words: White-tailed Sea Eagle', Haliaeetus albicilla; post-fledging movement', foraging habitat', anthropogenic food sources', Hokkaido, Japan. In Far East Asia, Hokkaido is the southernmost breed- ing area for White-tailed Sea Eagles {Haliaeetus albicilla). A small number of Wliite-tailed Sea Eagles breed in Hok- kaido and are considered resident. Many White-tailed Sea Eagles, along with Steller’s Sea Eagles {H. pelagicus) , also winter in Japan, mainly in Hokkaido. There are some reports on natal dispersal and move- ments of immatures for the European populations of White-tailed Sea Eagles (e.g., Helander 1980, Saurola 1981, Krol 1983, Sternberg and Saurola 1983, Meyburg et al. 1994). These authors reported that eagles mostly do not spend their first winter near their natal areas, and some immatures migrate long distances, exceeding 1000 km. However, similar information does not exist for these eagles in Asia. The objectives of this study were to mon- itor the movements of immature Wliite-tailed Sea Eagles from natal areas and to determine their foraging habi- tats. Study Area and Methods The Nemuro region in eastern Hokkaido is mostly a volcanic plain less than 100 m in elevation. Annual mean temperature is 5.7°C and the climate is characterized by a foggy and cold summer, and by a dry and cold winter (Miyawaki 1988). The seacoast is sometimes covered by sea ice in winter. Marsh vegetation has developed around inland-bays and lakes (Miyawaki 1988). A mixed forest consisting mainly of Sakhalin fir {Abies sachalinensis) and birch {Betula ermanii) is found on the shore terrace, and a broad-leaved forest consisting primarily of Japanese al- der {Alnus japonica) and Japanese elm {Ulmus davidiana) is distributed in the marshland (Miyawaki 1988). The plain was formerly covered with a broad-leaved forest dominated by oak ( Quercus mongolica) , but has been most- ly converted to pasture (Takenaka and Ono 1995). Twenty nestlings (4 wk of age) from eight nests in the Nemuro region were color-banded during 1992-95 (Fig. ' Present address: Wildlife Section, Nature Conservation Department, Hokkaido Institute of Environmental Sci- ences, Kita-19 Nishi-12 Kita-Ku, Sapporo, 060-0819, Ja- pan; present affiliation: Domestic Research Fellow, Japan Society for the Promotion of Science; e-mail address: shiraki@hokkaido-ies.go.jp 1). Color bands were made of plastic, 2. 5-3.0 cm high and the joint was glued with acetone. All individuals were marked with an unique combination of color bands. Nests were alphanumerically numbered (N1-N8) and nestlings were alphabetically coded (A-T). Eagles A-E hatched in 1992, F-L in 1993, M-O in 1994, and P-T in 1995. Seven of these color-banded nestlings were also fitted with radio-transmitters. Two siblings, M and N in N4 were fitted with a 9.8 g tail-mounted transmitter in 1994. The transmitters broadcast at 144 MHz and had a battery life expectancy of 1.5 yr. An approximately 23.0 g leg-band type transmitter was attached to the tarsus of two siblings, S and T in N8, and Q in N4, P in N6, and R in N7 in 1995. Battery-life expectancy of these transmitters was 2 yr. All nestlings were returned to their nests immediately after banding and radio-tagging. Monitoring of the nestlings in N4 were carried out by direct observations during June and July after attaching transmitters in 1994 and 1995. These observations were made at a distance of 800 m from the nest from dawn to dark at least every other day. To determine fledging day (the day of first flight) for each nestling at N4, the nest was observed every day starting on 26 June in 1994 and on 10 July in 1995. These observations continued until fledging. Radio-tagged fledglings were tracked upon de- parture from the natal areas. M and N were monitored at least once every three days during August, September, October, and December in 1994. Q was tracked during August and September in 1995. In most cases, I monitored birds and nests weekly to determine departure days for the other fledglings in 1995. Departure day was defined as the day when a fledg- ling was gone from the natal area and moved to another location. When a fledgling could not be located on the day of its disappearance from the natal area, the depar- ture date was recorded as the period from disappearance day to the day it was first relocated. When a fledgling disappeared from the place where it was relocated, the natal area was checked to determine if it had returned. I made an attempt to locate color-banded immature eagles from autumn 1992 until March 1997 by opportu- nistic observations at likely foraging sites from Notsuke Bay to Nemuro Peninsula, including coastal areas, a lake, rivers, a bay, and a fish factory (Fig. 1), and by interviews with local residents. Regular searches were also conduct- ed once or twice a month along a route that runs along the sea coast from Notsuke Bay to Nemuro Peninsula and 220 September 2002 Short Communications 221 N%muro Stratt Netnuro Penmtula W ReguUf t««rch area N* Neat alte m Pith factory N ^ i Birth Birth l Eagte place year A(j N1 1992 N1 1992 0 A N2 1992 F A N2 1993 G ■ N2 1993 J N1 1993 kO N3 1993 L ♦ N3 1993 Mifr N4 1994 N A N4 1994 OV N5 1994 Q ▼ N4 1995 RO N7 1995 s.g> NS 1995 0 5 10 km 1 t t Th* Sea of OkhoatM -45 00 N 43 00 N Pacific Ocmmn 143 00 £ STUDY AREA i4e 00 E I. Figure 1. Study area and locations of color-banded White-tailed Sea Eagles observed during and after their first winter in the Nemuro region. Numbers beside symbols indicate year of location and letters indicate season. Seasons are defined as Sp = spring (1 April-31 May), Su = summer (1 June-31 August), A = autumn (1 September-30 November), and W = winter (1 December— 30 March). around Furen Lake from December 1994-October 1996, and in January-February 1997 (Fig. 1). In this paper, eagles <1 yr of age are referred to as juveniles, and non-adult eagles (>1 yr and <5 yr of age) to as immatures. Results and Discussion Twelve (60%) of 20 color-banded eagles were observed after their first winter. Six (30%) of 20 eagles were ob- served after their second winter, and one (6.7%) of 15 eagles color-banded in 1992-94 was observed after its third winter. Accurate fledging dates were determined for three ra- dio-tagged juveniles from N4. They were 28 June 1994 for M, 30 June 1994 for N, and 12 or 13 July 1995 for Q. The dates of departures from the natal areas were deter- mined for four juveniles. They were between 8-12 Sep- tember 1994 for M and N, 9 September 1995 for Qfrom N4, and 13 September 1995 for P from N6. The intervals between fledging and departure were 8-1 1 wk. Previous studies found that, for Bald Eagles (H. leucocephalus) , the intervals were 7 or 8 wk (Gerrard et al. 1974), 5-10 wk (McCollough 1986), 2-5 wk (Hunt et al. 1992), 4.5-10 wk (McClelland et al. 1996) and 4-11 wk (Wood et al. 1998). Movements from the natal areas were recorded during the first autumn for six of seven radio-tagged juveniles and one color-banded juvenile (Fig. 2). The radio-trans- mitter of eagle R failed after 13 June 1995 and this bird was not re-sighted after 26 August 1995. Juveniles M, N, 222 Short Communications VoL. 36, No. 3 Nemuro Strait Furen Lake Total Rivef 0 5 10 km 1 » « N94 □ Q 95 Bettoga Rivef Onnebetsu Rivef Nest site ODI Radio-tagged A04 eagle * Color- ^ banded eagle Figure 2. Enlargement of area illustrated in Figure 1. Early movements of radio-tagged and color-banded juvenile White-tailed Sea Eagles from their nests in the Nemuro region. Numbers beside symbols indicate year of hatching and letters refer to individual eagles. Arrows indicate direction of travel. Q, and P moved from their natal areas to the Bettoga River in September (Fig. 2). Sibling juveniles S and T from N8 were occasionally detected around the natal area until 16 September 1995. They were relocated along the Onnebetsu River on 19 October 1995. Juvenile Kwas relocated in the first autumn at the east end of sandbar extending from northwestern part in Lake Furen. For all birds, the distance from the nest to the first location away from the nest ranged from 7.0 km to 22.0 km with no apparent preference for direction. Pink salmon ( Oncorhynchus gorbuscha) and chum salm- on (O. keta) are most abundant during August-Septem- ber, and October-December, respectively, in the rivers of Hokkaido (Ochiai and Tanaka 1986, Nagasawa and To- risawa 1991). Departures from the natal areas in this study seemed to correspond with the timing of salmon runs. Numerous salmon carcasses were observed on the Bettoga River between the estuary and a weir dam 4.0 km upstream from the mouth in September-October 1994. White-tailed Sea Eagles, including color-banded ju- veniles, and Steller’s Sea Eagles were both observed on the Bettoga River feeding on salmon carcasses on the riverbanks, in shallow water and on the tidal flat at low tide. Marked juvenile White-tailed Sea Eagles were also seen on the Onnebetsu and Tobai Rivers in their first autumn (Fig. 2) . Similarly, in parts of its range, the move- ments of post-fledging Bald Eagles are influenced by spawning salmon (Servheen and English 1979, Hodges et al. 1987). Abundant salmon carcasses are particularly important as easily-available prey for inexperienced ju- veniles (McClelland et al. 1983, Stalmaster and Gessaman 1984, Restani 2000). Fourteen of the marked eagles were found during and after the first winter in their natal areas (Fig. 1). Juveniles Q and S were observed in areas where people supplied food, including the fish factory and Furen Lake, during their first winter. At the fish factory, fish offal was dumped on the ground, and on Furen Lake and Notsuke Bay, from the end of December to the end of March fishermen discarded rough fish on the ice. Eagles A, J, N, and Q, were resighted at two or more locations (Fig. 1), eagle A most frequently (five times at three different places between its third summer and its fifth winter). Immature White-tailed Sea Eagles in Eu- rope may disperse to areas of abundant food (Love 1983). Similarly, the movements of immature Bald Eagles are nomadic and variable (McClelland et al. 1994, Jen- kins et al. 1999), and are associated vdth temporary con- centrations of prey and carrion (Harmata et al. 1999) Based on my observations, I suggest that juvenile White- tailed Sea Eagles moved among habitats probably in re- sponse to food availability. In spring and summer, immature eagles were found on Furen Lake, Notsuke Bay and on the coast (Fig. 1). These sites had two possible food resources: “natural food,” such as fish, waterfowl (e.g.. Anas spp., Aythya spp.), and seagulls; and “anthropogenic food,” rough September 2002 Short Communications 223 fish discarded by commercial fishermen on the tidal flats and shores. During autumn, color-banded eagles were mostly ob- served on rivers, especially on the Bettoga River (Fig. 1). The rivers in the natal area are important sources of salmon carrion in autumn, not only for first-year eagles, but also for older immatures. During winter, most eagles were found at the fish fac- tory and at Furen Lake when it was frozen (Fig. 1). Most White-tailed Sea Eagles and Steller’s Sea Eagles that win- tered in Hokkaido gathered at places where people sup- plied fish (Working Group for White-tailed Eagles and Steller’s Sea Eagles 1996), probably because sufficient amounts of natural prey were not available (Shiraki 2001). Field observations and ring recoveries in Sweden and Finland suggested that survival, especially of first-year eagles, was improved by a supplemental winter-feeding program (Helander 1985). Survival of immature White- tailed Sea Eagles hatched in the Nemuro region also may be enhanced by anthropogenic sources of food. Resumen. — Los movimientos de las areas de natalidad y de los habitats de forrageo de juveniles de Haliaeetus al- bicilla, fueron examinados con telemetria y con observa- ciones de aves marcadas. La dispersion de las areas de natalidad ocurrieron entre el 8-13 de septiembre, cuan- do los salmones {Salmo spp.) depositaron sus huevos y fueron abundantes en los rios cercanos. Las aguilas ju- veniles probablemente se movilizaron entre los habitats en respuesta a la disponibilidad de comida. En primavera y verano, las aguilas juveniles fueron observadas en areas costeras y en lagos cercanos durante el otono, las aguilas juveniles fueron observadas principalmente en los rfos en donde se alimentaron de restos de salmon. En invierno, las aguilas juveniles dependieron de restos de comida provenientes de desechos humanos, tales como peces y despojos de reses muertas. La sobrevivencia de juveniles reproducidos en la region de Nemuro, Japon puede estar reforzada por alimento de origen antropico. [Traduccion de Cesar Marquez] Acknowledgments 1 thank T. Matsuo, S. Yamamoto, N. Rondo, M. Takada, N. Aoki, H. Nakagawa, M. Tazawa, K. Saito, M. Sugano, and R. Takada for help in color-banding and for precious information on marked-eagles. 1 also thank F. Sato for suggestions on color-banding, and M. Ueta, RF. Schempf, M.J. McGrady, and S. Tsuyuzaki for improving an early draft of this manuscript. R.E. Yates, M.J.R. Miller, and an anonymous reviewer provided helpful comments on the manuscript. This study was conducted partly as a project of the Environmental Agency of Japan and funded by World Wide Fund for Nature of Japan. Literature Cited Gerrard, R, J.M. Gerrard, D.W.A. Whitefield, and WJ. Maher. 1974. Post-fledging movements of juvenile Bald Eagles. Blue Jay 32:218-226. Harmata, A.R., GJ. Montopoli, B. Oakitaf, RJ. Har- MATA, AND M. Restani. 1999. Movements and survival of Bald Eagles banded in the Greater Yellowstone Eco- system. J. Wildl Manage. 63:781-793. Helander, B. 1980. Colour-banding of White-tailed Sea Eagles {Haliaeetus albicilla L.) in northern Europe — a progress report. Fauna Flora 75:183-187. . 1985. Winter feeding as a management tool for White-tailed Sea Eagles in Sweden. Pages 421-427 in I. Newton and R.D. Chancellor [Eds.], Conservation studies on raptors; Proceedings of the ICBP World Conference on Birds of Prey. ICBP Tech. Publ. No 5 ICBP, Cambridge, U.K. Hodges, J.I., E.L. Boeker, and A.J. Hansen. 1987. Move- ments of radio-tagged Bald Eagles, Haliaeetus leucoce- phalus, in and from southeastern Alaska. Can. Field- Nat. 101:136-140. Hunt, W.G., R.E. Jackman, J.M. Jenkins, C.G. Thelan- der, and R.N, Lehman. 1992. Northward post-fledging migration of California Bald Eagles. J. Raptor Res. 26 19-23. Jenkins, J.M., R.E. Jackman, and W.G. Hunt. 1999. Sur- vival and movements of immature Bald Eagles fledged in Northern California./. Raptor Res. 33:81-86. Krol, W. 1983. Movements of White-tailed Eagles {Hal- iaeetus albicilla) of Central and Eastern Europe. Ring 114- 115:97-103. Love, J.A. 1983. The return of the sea eagle. Cambridge Univ. Press, Cambridge, U.K. McClelland, B.R., L.S. Young, D.S. Shea, RT. Mc- Clelland, H.L. Allen, and E.B. Spettigue. 1983. The Bald Eagle concentration in Glacier National Park, Montana: an international perspective for manage- ment. Pages 69-77 in D.M. Bird [Ed.], Biology and management of Bald Eagles and Ospreys. Harpell Press, Ste. Anne de Bellevue, Quebec, Canada. , L.S. Young, RT. McCleliand. J.G. Crenshaw, H.L. Allen, and D.S. Shea. 1994. Migration ecology of Bald Eagles from autumn concentrations in Glacier National Park, Montana. Wildl. Monogr. No. 125. , RT. McClelland, R.E. Yates, E.L. Caton, and M.E. McFadzen. 1996. Eledging and migration of ju- venile Bald Eagles from Glacier National Park, Mon- tana. /. Raptor Res. 30:79—89. McCollough, M.A. 1986. The post-fledging ecology and population dynamics of Bald Eagles in Maine. Ph.D dissertation. Univ. Maine, Orono, ME U.S.A. Meyburg, B.-U., T. Blohm, C. Meyburg, I. Borner, and P. Sommer. 1994. Satellite and ground tracking of a young White-tailed Sea Eagle Haliaeetus albicilla in the Uckermark: reintegration in the brood, break-up of the family, dispersion and wintering. Vogelwelt 115 115- 120. Miyawaki, a. [Ed.]. 1988. Vegetation of Japan. Vol. 9. Hokkaido, Shibundo Co. iTd. Publishers, Tokyo, Ja- pan. Nagasawa, K. and M. Torisawa [Eds.]. 1991. Eishes and 224 Short Communications VoL. 36, No. 3 marine invertebrates of Hokkaido: biology and fish- eries. Kita-nihon Kaiyo Center Co. Ltd. Sapporo, Ja- pan. OcHiAi, A. AND M. Tanaka. 1986. Ichthyology II. Koseisya- koseikaku, Tokyo, Japan. Restani, M, 2000. Age-specific stopover behavior of mi- grant Bald Eagles. Wilson Bull. 112:28-34. Saurola, P. 1981. Ringing of the White-tailed Eagles in Einland. Pages 135-145 in Stjernberg, T. [Ed.], The White-tailed Eagle Projects in Einland and Sweden. Jord-Och Skogsbruksministeriet, Helsinki, Finland. Servheen, C. and W. Engijsh. 1979. Movements of re- habilitated Bald Eagles and proposed seasonal move- ment patterns of Bald Eagles in the Pacific Northwest. Raptor Res. 13:79-88. Shiraki, S. 2001. Foraging habitats of Steller’s Sea Eagles during the wintering season in Hokkaido, Japan. J. Raptor Res. 35:91-97. Stalmaster, M.V. and J.A. Gessaman. 1984. Ecological energetics and foraging behavior of overwintering Bald Eagles, Ecol. Monogr. 54:407-428. Stjernberg, T. and P. Saurota. 1983. Population trends and management of the White-tailed Eagle in north- western Europe. Pages 307-318 in D.M. Bird. [Ed.], Biology and management of Bald Eagles and Ospreys. Harpell Press, Ste. Anne de Bellevue, Quebec, Cana- da. Takenaka, T. and Y. Ono. 1995. Values of riparian forests in the Nishibetsu river, Konsengenya plain. Eastern Hokkaido. Proc. Architecture 127:122-129. Wood, P.B., M.W. Collopy, and C.M. Sekerak. 1998. Postfledging nest dependence period for Bald Eagles in Florida. J! Wildl. Manage. 62:333—339. Working Group for White-tailed Eagles and Steller’s Sea Eagi.es. 1996. Wintering status of Steller’s Sea Ea- gles and White-tailed Eagles in northern Japan. Pages 1-9 in Survey of the status and habitat conditions of threatened species, 1995. Environment Agency, To- kyo, Japan. Received 13 November 2001; accepted 22 May 2002 Associate Editor: Marco Restani J Raptor Res. 36(3):224-228 © 2002 The Raptor Research Foundation, Inc. Habitat Preferences, Breeding Success, and Diet of the Barn Owi. {Tytoalba) in Rome: Urban versus Rural Territories Luca SalvatP Piazza F. Morosini 12, 1-00136 Rome, Italy Lamberto Ranazzi Via Livorno 85, 1-00 1 62 Rome, Italy Alberto Manganaro Via di Donna Olimpia 152, 1-00152 Rome, Italy Key Words: Barn Owl; Tyto alba; territories; habitat pref- erences; breeding success; feeding habits; urban habitat; Rome. Population density of the Barn Owl (Tyto alba) is de- pendent on available supply of small rodents in both the territory and home range (e.g., De Bruijn 1994, Taylor 1994) . Moreover, habitat and nest quality are decisive fac- tors in determining distribution, breeding success, and feeding habits of Barn Owls (De Bruijn 1994, Taylor 1994, Poprack 1996, Martinez and Lopez 1999, Zubero- goitia 2000, Baudvin and Jouaire 2001). The decrease in numbers of this owl in central Europe is probably related ^ E-mail address: picoidesmajor@yahoo.com to the development of new agricultural practices and loss of traditional nest sites (De Bruijn 1994). In Mediterra- nean Europe, owl populations seem to be more stable, likely due to a milder climate and large supply of prey (Martinez and Lopez 1999, Zuberogoitia 2000), but fur- ther information is needed. Barn Owls commonly breed in urban areas that pro- vide suitable nest sites (e.g., Baudvin and Jouaire 2001). The ecology of the Barn Owl is poorly known in urban habitats and no direct comparisons with neighboring habitats are available. Here, we compare data on distri- bution, territory characteristics, habitat preferences, breeding success, and feeding habits of Barn Owls from urban and rural areas in central Italy. Understanding September 2002 Short Communications 225 habitat preferences of this species of special concern in relation to population parameters and feeding habits may provide useful management information for a vari- ety of habitats, including rural and urban areas. Methods The study was carried out in Rome, Italy (41°53'N, 12°28'E) from spring 1995-summer 2001; urban areas included small gardens with Pinus pinea, Cupressus semper- virens, Cedrus sp., and Quercus spp. Rural areas included open lands with grassy pastures, uncultivated helds, and small forest patches, mainly of Q. ilex and Q. suber (Ran- azzi et al. 2000). We surveyed hve census plots distributed along the ur- ban gradient that included the main habitats in the study region. Nest sites and daytime roosting sites were searched for the presence of Barn Owls. Pellets, feathers, and droppings near possible nests were considered evi- dence for the occupation of a site. Records of territorial screeches and calls of young were collected systematically during the entire study period and were combined with the other data to locate nests. Spacing among occupied nests was calculated for each plot by the nearest-neighbor method using data from 1997 breeding season. Regular- ity in nest spacing was computed for each area with the G-test (Ranazzi et al. 2000). We measured percentages of (1) open lands, (2) de- ciduous woods, (3) conifer woods, (4) urban gardens, (5) developed areas (buildings and homes), (6) Roman ru- ms, and (7) waterbodies in a circular plot with a radius of 1.5 km centered in the nest site (Michelat and Girau- doux 1991) at 10 urban and 7 rural Barn Owl nests whose occupation was confirmed throughout the study period. The same variables were measured in 15 unoc- cupied sites randomly selected along the urban gradient m the five plots surveyed. We compare each variable mea- sured at urban and rural territories and at occupied and random sites by Mann-Whitney Gtests. A sequential Bon- ferroni test was used to adjust the significance level to the number of comparisons using the same data set {N = V). No data on clutch size were collected to minimize dis- turbance of the adult owls. Moreover, many nests located m scaffolding holes of old buildings were inaccessible for inspection of eggs. Visits to nests were limited to a period when young were ca. 3-6 wk of age (De Bruijn 1994). We studied diet by analyzing pellets collected (April- August) in 15 stable territories classified as urban or rural based on the percentage of developed areas (urban: >50% developed in the circular plot with a radius of 1.5 km centered in the nest site) . Prey remains were identi- fied using diagnostic keys and by comparison with mu- seum specimens (e.g., Piattella et al. 1999). Differences in diet composition between urban and rural diets were tested using a contingency table which included all the prey groups reported in Table 1. We used distance of each pellet site to the center of the city (Ranazzi et al. 2000) as a relative index of the proportion of urban areas around owl sites. Spearman rank correlations were per- formed between the percentage of each prey group (Ta- ble 1) and the distance to the city center. Table 1 . Percent of prey types recorded in the prey re- mains at Barn Owl nest and roost sites in urban areas of Rome, central Italy. Urban Sites N= 7 Rural Sites N = 8 Invertebrates 0.69 1.18 Anura 0.00 0.05 Reptilia 0.13 0.00 Columbidae 0.25 0.10 Sturnus vulgaris 1.01 0.00 Passer spp. 4.53 0.88 Fringillidae 0.94 0.25 Other Passeriformes 2.96 1.97 AVES total 9.69 3.19 Suncus estruscus 1.89 3.14 Crocidura spp. 2.14 3.98 Talpa sp. 0.00 0.15 INSECTWORA total 4.03 7.27 Chiroptera 1.01 1.77 Muscardinus avellanarius 0.00 3.34 Microtus savii 59.18 41.52 Apodemus spp. 5.72 22.36 Rattus spp. 2.83 1.23 Mus domesticus 16.67 15.23 Other mammalia 0.06 2.85 RODENTIA total 84.47 86.54 Total prey (N) 1590 2035 Results Based on the distribution of 31 Barn Owl territories, density was generally higher than those recorded in cen- tral Europe (Table 2). Mean nest spacing ranged from 1.8 km-3.0 km. The G-test (0.78) indicated a substantial regularity in nest distribution. Mean density in the sub- areas surveyed ranged from 8-21 territories/km^. Open lands contributed half the available area of the census plots in rural territories; this decreased in urban territories. Wooded and developed areas made up the remaining part of rural and urban territories, respectively (Eig. 1). The percentages of both deciduous and conifer woods, as well as of urban gardens showed significant differences between urban and rural territories (decidu- ous woods: U ~ 0, P = 0.0006; conifer woods: U = 0, P < 0.001; urban gardens: U = 6.5, P = 0.005). Occupied territories contained a significantly higher proportion of open lands than random plots (Table 3), but a lower proportion of vegetable gardens and developed areas. Out of 14 breeding attempts, 2 failed (14.3%), 1 pro- duced one fledgling (6.7%), 7 produced two fledglings (50.0%), 3 produced three fledglings (14.3%), and 1 produced four fledglings (6.7%). The mean number of 226 Short Communications VoL. 36, No. 3 Table 2. Breeding density of Barn Owls from selected European studies. Study Region Census Period Census Area (km^) Mean Density (Terri- tories/ 100 km2) Source Poland, Krakow 1991-95 6289 0.8 Bartmanska et al. 2000 Czech Rep., Olomouc 1983-95 1451 1.3 Poprack 1996 South Poland 1984-88 1640 1.4 De Bruijn 1994 West Germany 1960-72 841 1.7 De Bruijn 1994 Netherlands, Liemers 1967-84 250 2.4 De Bruijn 1994 Southwest Scotland 1981-85 2200 3.2 De Bruijn 1994 East Germany 1968-74 1000 3.3 De Bruijn 1994 Netherlands, Achterhoek 1967-84 250 5.3 De Bruijn 1994 Germany, Bergenhusen 1974-79 100 10.0 De Bruijn 1994 Italy, Rome 1995-2001 241 12.8 This study Figure 1. Percentage of different habitat cover types found within a 1.5 km diameter plot centered on Barn Owl nests in urban (N = 10) and rural {N = 7) areas in Rome. Error bars represent the SD around the mean percentage of each land cover variable. September 2002 Short Communications 227 Table 3. Percentages of seven land cover variables (mean ± SD) in seventeen occupied territories and fifteen random sites in Rome, central Italy. Variable Occupied Territories Random Sites P-Level Deciduous woods 15.2 ± 20.1 1.5 ± 2.3 0.02 Conifer woods 6.5 ± 10.6 0.7 ± 1.3 0.02 Urban gardens 4.6 ± 7.1 15.9 ± 8.8 0.001* Open lands 43.4 ± 32.1 2.0 ± 2.4 <0.0001* Waterbodies 0.1 ± 0.3 1.3 ± 3.5 0.83 Roman ruins 5.3 ± 14.3 1.2 ± 2.1 0.35 Developed areas 25.0 ± 32.2 77.5 ± 11.1 0.0001* * P < 0.05 based on Mann-Whitney U-test after Bonferroni correction — see methods for details. fledglings was 2.0 (SD = 1.2) per breeding pair and was low compared to data collected in central Europe (Table 4). Urban owls reared more fledglings than rural ones (2.3 vs. 1.7 fledglings per breeding pair, N = 7 breeding attempts per each habitat), but this difference was not signihcant ( U = 10, P = 0.20) . Based on 3625 prey analyzed, rodents (Rodentia) and shrews (Insectivora) represented 94% of total prey in Barn Owl diets from rural sites and 88% in urban sites (Table 1). Birds, especially sparrows, increased in urban areas. Differences in diet composition between urban and rural sites were significant (x^ = 436.74, P < 0.001, df = 17). The percent numbers of Crocidura shrews (r^ = 0.58, P= 0.02, N= 15), Muscardinus dormice?, (r^ = 0.52, P = 0.05, N = 15), and Apodemus mice (r^ = 0.64, P = 0.01, N = 15) increased with the distance to the city cen- ter. The percent numbers of both Microtus voles (r^ = — 0.66, P = 0.007, N = 15) and rats (r^ = —0.73, P = 0.002, N = 15) strongly decreased with the distance to the city center. Discussion The close nest spacing in our study area is probably due to high availability of nest sites (De Bruijn 1994, Baudvin andjouaire 2001). In urban areas, mins, towers, and old farmhouses provided a surplus of nest cavities. Barn Owls primarily defend their nest sites rather than a breeding territory around them; thus, feeding areas over- lap extensively and are dynamic depending on nest sup- ply and prey densities (Taylor 1994). Stable weather typ- ical of the Mediterranean basin may further account for high population levels in Rome, compared to more for- ested rural areas. In both urban and rural sites, open lands represented the primary foraging habitat found within Barn Owl nesting areas (De Bruijn 1994) and the proportion of open habitats was significantly less at ran- dom sites (Table 3). Ruins and gardens were abundant in urban territories providing more foraging areas for owls at these sites compared with rural areas. The breeding success, although based on a limited sample, was lower than those recorded in central Europe The abundance of rodents has been reported to strongly influence the reproduction of Barn Owls (Taylor 1994) Owls in areas with generally drier climates probably have lower prey densities (e.g., Herrera and Hiraldo 1976) compared to populations from central Europe, and a re- duction in the availability of rodents seems plausible to explain the low breeding rate in Rome. The switch to- Table 4. Breeding success of Barn Owls from selected European study areas. Study Region Duration OE Study (Years) Mean Fledglings per Pair Source Czech Rep., Olomouc 12 5.0 Poprack 1996 Slovakia 4 4.5 Sarossy 2000 East Germany 7 4.3 Taylor 1994 France, Burgundy 25 4.0 Baudvin andjouaire 2001 Germany, Saarland 5 3.9 Poprack 1996 Southwest Scotland 13 3.2 Taylor 1994 Holland 6 3.1 De Bruijn 1994 Spain, Vizcaya 6 2.2 Zubergoitia 2000 Italy, Rome 5 2.0 This study 228 Short Communications VoL. 36, No. 3 ward synantropic rodents and birds in the diet at urban sites reflects the reduction of prey diversity that occurs in such areas and indicates the variation in the availability of small mammal species along the urban gradient (Piat- tella et al. 1999). The predation on abundant rat popu- lations may explain locally high breeding success in ur- ban areas compared to neighboring farmlands (Martinez and Lopez 1999). Resumen. — Recolectamos datos (1995-2001) sobre ladis- tribucion, caracteristicas del territorio, preferencias de habitats, tasas de reproduccion y habitos alimenticios de la lechuza de campanario {Tyto alba), en reproduccion en zonas rurales y urbanas de Roma, Italia. La distancia entre nidos oscilo entre 1.8 km. A 3.0 km. Los territorios urbanos incluyeron mas espacio abierto que los rurales. Los territorios de las lechuzas contenian un mayor por- centaje de areas boscozas (21.7%) que los sitios escogidos al azar (2.2%). El numero medio de volantones produ- cidos por pareja en reproduccion (2.0 ± 1.2) fue inferior a aquellos registrados para el centro de Europa. Eos roe- dores representaron el 94% de las presas en areas rura- les, pero solo el 88% en sitios urbanos. Los roedores del genero Microtus y las ratas, dominaron la dieta de los si- tios urbanos, mientras que los del genero Apodemus y Muscardinus fueron depredados en sitios rurales. Un cli- ma estable y el aprovisionamiento de nidos, probable- mente contribuyeron a los altos niveles de poblacion en Roma. Una reduccion general de pequenos mamiferos en las areas secas del Mediterraneo puede explicar el bajo exito reproductivo comparado con las poblaciones del centro de Europa. [Traduccion de Cesar Marquez] ACKNOWITDGMENT.S We are grateful to C. Marti, V. Penteriani, F. Ziesemer, and an anonymous referee who made comments and valuable criticism on an early draft of the manuscript. Eiterature Cited Bartmanska, J., A. Pawlowska-Indyk, and F. Indyk. 2000. Distribution of the Barn Owl ( Tyio alba) in the east part of Lower Silesia province (Poland). Buteo 11:35- 42. Baudvin, H. and S. Jouaire. 2001. Breeding biology of the Barn Owl ( Tyto alba) in Burgundy: a 25 year study (1971-1995). Buteo 12:5-12. De Bruijn, O. 1994. Population ecology and conservation of the Barn Owl Tyto alba in farmland habitats in Lie- mers and Achterhoek (The Netherlands). Ardea 82:1- 109. Herrera, C.M. and F. Hiraldo. 1976. Food-niche and trophic relationships among European owls. Ornis Scand. 7:29-41. Marti, C.D. 1988. A long-term study of food-niche dy- namics in the common Barn Owl: comparison within and between populations. Can.]. Zool. 66:1803-1812. Martinez, J.A. and G. Lopez. 1999. Breeding ecology of the Barn Owl {Tyto alba) in Valencia (SE Spain)./. Ornithol. 140:93-100. Michelat, D. and P. Giraudoux. 1991. Dimension du domaine vital de la chouette effraie Tyto alba pendant la nidification. Alauda 59:137-142. PlATTELLA, E., L. SALVATI, A. MANGANARO, AND S. FATTO- RiNi. 1999. Spatial and temporal variations in the diet of the European Kestrel {Falco tinnunculus) in urban Rome, Italy. / Raptor Res. 33:172-175. PoPRACK, K. 1996. Hnizdni biologie a zmeny pocetnosti sovy palene {Tyto alba) v okrese Olomouc. Buteo 8:39- 80. Ranazzi L., a. Manganaro, and L. Salvati. 2000. Wood- land cover and territory density of Tawny Owls Strix aluco in a Mediterranean urban area. Biota 1:83-92. Saros.sy, M. 2000, Ku hniezdeniu a migracii plamienky driemavej {Tyto alba) na Slovensku. Buteo 11:25-34, TAYL.OR, I. 1994. Barn Owls. Predator-prey relationship and conservation. Cambridge Univ. Press, Cambridge, U.K. ZuBEROGOlTiA, I. 2000. La influencia de los factores met- ereologicos sobre el exito reproductor de la Lechuza Comun. Ardeola 47:49-56. Received 12 November 2001; accepted 24 April 2002 /. Raptor Res. 36(3);229-230 © 2002 The Raptor Research Foundation, Inc. Incidence oe Naturally-healed Fractures in the Pectoral Bones oe North American Accipiters Aaron J. Roth^ and Gwilym S. Jones Center for Vertebrate Studies, Department of Biology, Northeastern University, Boston, MA 02115 U.S.A. Thomas W. French Massachusetts Division of Fisheries and Wildlife, Natural Heri tage and Endangered Species Program, Westboro, MA 01581 U.S.A. Key Words: Accipter; Sharp-shinned Hawk, Accipiter striatus; Cooper’s Haxvk; Accipiter cooperii; Northern Gos- hawk; Accipiter gentilis; fractures'. North America; injuries. The theory of skeletal strength proposed by Alexander (1981, 1984) suggests that optimal bone strength evolved to minimize risk of fracture. Alexander theorized that a balance between risk of bone failure and energy cost of growth and utilization of heavier skeletons should be achieved through natural selection. He further suggested that fracture incidence should increase as the cost of in- jury falls. Studies of fractures in wild populations are po- tentially useful in testing this theory. Few such studies have been published. In this study, we focused on healed fractures to the pec- toral girdle in three species of Accipiter. Members of this genus are specialized forest predators that primarily use a series of perch and scan periods from the concealment of tree branches and bushes before chasing prey (Bent 1937). The Sharp-shinned Hawk {Accipiter striatus), pri- marily a small-bird predator, Cooper’s Hawk (A. cooperii), and Northern Goshawk {A. gentilis), both more general- ized small-mammal and bird predators, hunt in this man- ner (Reynolds and Meslow 1984). This type of hunting behavior may lead to collisions with branches and other such obstacles. Therefore, evidence of fractures should be present in these species, given that the cost of such injury is low enough to enable individuals to recover. Methods Skeletal specimens {N = 339) of accipiters were visually inspected for evidence of healed fractures to the pectoral girdle (furcula, scapula, and coracoid) . The pectoral gir- dle was chosen due to its importance to flight and its potentially higher susceptibility to breakage from head- on impact. Healed fractures were identihed by the pres- ence of bone callus associated with fracture lines. Species examined were A. cooperii {N = 115: 37 males, 64 females, 14 unknown sex), A. gentilis (N = 52: 26 males, 22 fe- males, 4 unknown sex) and A. striatus {N= 172: 65 males, 90 females, 17 unknown sex). Birds that were known to have been captive for any period of time were not in- cluded. 1 E-mail address: aroth80@hotmail.com Specimens were collected between 1921 and 1998. The frequencies of birds with healed fractures collected from each decade were compared to determine if rates increased with time. Due to smaller sampler sizes it was not possible to compare frequencies from the 1920s, 1940s, and 1960s Results Evidence of healed fractures was found in 18.6% (63 hawks with 67 fractures) of the individuals {N = 339) There was no significant difference among the species (X^ = 1.78, df = 2, P > 0.25; Table 1). There was also no significant difference between the combined sexes (sexes were combined to increase sample size) (x^ = 0.96, df = 1, T> 0.25; Table 1). The majority of fractures occurred in the furcula (16%, N= 54), 12 fractures were found in the scapula (4%); and only one healed fracture was found in the coracoid (0.3%). Fractures occurred in varying locations in both the furcula and scapula. Frac- tures at the center of the furcula (i.e., point of fusion of the clavicles) were common as well as fractures near or at the midpoint of each clavicle shaft. Fractures of the scapula were most often at either the extreme distal end or near the center. Scapular fractures sometimes healed at an angle (e.g., one scapula healed at the midpoint of the bone at an angle of about 45°) . There was no signif- icant difference between the frequencies of healed frac- tures in birds collected during the 1930s, 1950s, 1970s, 1980s, and 1990s (x^ = 2.01, df = 4, P > 0.50). Discussion The incidence of healed pectoral fractures confirms that impact injuries occur in accipiters and that some are able to recover. The cause of fractures could not be determined from museum specimens. There were no biases in fracture incidences with respect to species and sex (Table 1). We suggest that both natural and anthropogenic causes were involved in fractures. If anthropogenic causes were more significant than natural causes, than fracture incidence would be expected to increase through time due to in- creased urbanization. However, this was not the case. Raptor rehabilitation efforts have increased since 1960 (T. French pers. comm.). This could affect healed frac- ture incidence for birds collected in subsequent years. Our data showed no significant change in the fracture 229 230 Short Communications VoL. 36, No. 3 Table 1. Incidence of healed pectoral-bone fractures in each of the three North American Accipiter species. Number OF Fracture Fractures Incidence Cooper’s Hawk {N = 115) 26 23% Northern Goshawk (A = 52) 10 19% Sharp-shinned Hawk (A = 172) 27 16% Total male (A = 128) 29 23% Total female (A = 176) 31 18% Unknown sex (A = 35) 3 9% rates for years before and after 1960, suggesting that re- habilitation is not a factor. Healed fracture incidence represents only birds that sur- vive injury. Therefore, the incidence of impact injury to the pectoral girdle in accipiters may be higher than that found in this study, especially in urban habitats. Boal and Mannan (1999) found that collision with man-made ob- jects were responsible for 69.8 percent of mortalities of Cooper’s Hawks in an urban environment. Many of the specimens used for this study were collected during mi- gration, making it impossible to know if they frequented rural or urbanized habitats during the breeding and win- ter seasons. The fact that fracture incidence did not in- crease through time with increased urbanization suggests that either anthropogenic causes of fracture are not more significant than natural causes or that birds are less likely to survive collision with man-made structures. Further studies of fracture incidence among urban versus rural birds are needed. Also, the scarcity of healed coracoid frac- tures could be the result of less frequent injury to this bone, or birds are less likely to survive coracoid injury. Peregrine Falcons {Falco peregtinus) with broken coracoids are unable to fly well enough to catch prey and, therefore, are unable to recover (T. French pers. observ.). Previous studies have focused on healed fractures in the long bones of wild birds. Brandwood et al. (1986) examined wild-caught individuals from three avian fami- lies for incidence of long-bone fractures. They found a fracture incidence of 0.4% for total bones examined in anatids, 0.4% and 0.5% in two larid samples and 0.2% in columbids. It was theorized from these data that most birds would be either unlikely to suffer fractures or would not survive them (Brandwood et al. 1986). Accipiters rep- resent an exception to this hypothesis as do members of the genus Gyps. In a small sample of White-backed Vul- tures (G. africanus) and Rueppell’s Griffons (G. rueppel- lii), Houston (1993) found a 20% incidence of healed ulnar fracture. Unlike accipiters, these vultures do not engage in high-risk behavior. Houston theorized that the high fracture incidence in Gyps is due to skeletal fragility related to extreme weight reduction. Considering the importance of flight to accipitrine hunting style, it is significant that these birds are able to recover from a pectoral-bone fracture. This suggests the cost of such an injury is sufficiently low as to balance the risk of collision inherent in the behavior of this genus. In addition, the susceptibility to fracture of the furcula and scapula in accipiters may be compensated by the low- er energy cost of a light skeleton. Resumen. — Especimenes de Museo {N = 339) de Accipiter striatus, A. cooperii y Accipiter gentilis fueron examinados debido a la evidencia de fracturas soldadas naturalmente en el hueso pectoral. La incidencia general de las frac- turas fue del 19%. No hubo diferencia en la frecuencia de fracturas entre las tres especies o entre sexos. La may- oria de las fracturas ocurrieron en la “furcula.” La fre- cuencia de las fracturas soldadas sugieren que las heridas causadas por impacto son comunes en los accipiters, y que algunos individuos son capaces de recuperarse. [Traduccion de Cesar Marquez] Acknowledgments The authors thank the curators and collections manag- ers of museums and universities that loaned specimens for this study: J. Gerwin (North Carolina Museum of Natural Sciences [NCSM]), J. Hinshaw (University of Michigan Museum of Zoology [UMMZ]), D. Lee (NCSM), K. McGowan (Cornell University), R. Payne (UMMZ), T. Pe- terson (University of Kansas Natural History Museum [UKNHM]), M. Robbins (UKNHM), D. Causey (Museum of Comparative Zoology at Harvard University), D. Stead- man (University of Florida Natural History Museum [UFNHM]), and T. Webber (UFNHM). Specimens from the Center for Vertebrate Studies at Northeastern Univer- sity were also examined. The authors also thank G.C. Ar- gyros for his comments on an earlier draft of this paper. Literature Cited Aitxander, R. McN. 1981. Factors of safety in the struc- ture of animals. Sci. Prog. Land. 67:109-130. . 1984. Optimum strength for bones liable to fatigue and accidental damage.^ Theor. Biol. 109:621-636. Bent, A.C. 1937. Life histories of North American birds of prey, part one. U.S. Natl. Mus. Bull. 167. Boat, C.W., and R.W. Mannan. 1999. Comparative breeding ecology of Cooper’s Hawks in urban and exurban areas of southwestern Arizona. J. Wildl. Manage. 63:77-84. Brandwood, A., A.S. Jayes, and R. McN. Ai.exander. 1986. Incidence of healed fracture in the skeletons of birds, molluscs and primates. / Zool. Lond. 208:55-62. Houston, D.C. 1993. The incidence of healed fractures to wing bones of White-backed and Ruppell’s Griffon Vultures Gyps africanus and G. rueppellii and other birds. Ibis 135:468—475. Reynolds, R.T. and E.C. Mesl.OW. 1984. Partitioning of food and niche characteristics of coexisting Accipiter during breeding. Auk 101:761-779. Received 4 December 2001; accepted 23 May 2002 Associate Editor: Clint Boal /, Raptor Res. 36(3):231-235 © 2002 The Raptor Research Foundation, Inc. Plasma Chemistry Reference Values in Free-living Bonelli’s Eagle ( Hieraaetus fasciatus) Nestlings Javier Balbontin^ and Miguel Ferrer Department of Applied Biology, Estacion Biologica de Donana, Consejo Superior de Investigaciones Cientificas, Avda de Maria Luisa s/n, Pabellon del Peru, Sevilla 41013 Spain Keywords: Bonelli’s Eagle, Hieraaetus fasciatus; blood\ free-living nestling, plasma chemistry, sex. Few studies dealing with plasma biochemistry and physiology in wild birds can be found in the scientific literature. Most research papers deal with domestic or captive birds kept in zoos, rehabilitation facilities, or re- search centers (Lewandoski et al. 1986, Redig 1991, Fer- rer 1993, Dobado-Berrios et al. 1998). The knowledge of normal reference values in plasma for wild species is very important to a wide range of multidisciplinary subjects. Veterinarians need to have this information in order to better diagnose the condition of wild birds entering into rehabilitation centers or zoos (Lepoutre et al. 1983, Coo- per et al. 1986). Also, information gathered from he- matological research is of a great importance for ecolo- gists because such data may provide insights into the health of individuals being studied. Body condition that IS related to other ecological factors such as survival, fe- cundity, or habitat quality, could be estimated by levels of urea, uric acid, and other blood parameters (Cherel et al. 1987, Ferrer et al. 1987, Garcia-Rodriguez et al. 1987, Robin et al. 1987). It is important to know normal blood parameter ref- erence values for endangered species involved in a rein- troduction or restoration program in order to better un- derstand the physiological status of the released birds. Normal reference values in blood chemical constituents are known only for 5% of bird species which have been studied mostly in captive situations (Ferrer 1993). Although most of the information available comes from captive birds, it might be expected that a captive condition might affect hematological values (Bell and Freeman, 1971, Miglirioni et al, 1973, Wolf et al. 1985, Sturkie 1986, Ferrer et al, 1987, Garcia-Rodriguez et al. 1987). Factors such as age or sex influence the total var- iation found in plasma enzymes, proteins, metabolites, and other organic molecules. However, presently these factors are poorly understood due to difficulty of gath- ering information on different age-classes in wild species. Other factors affecting values of chemical components in plasma are circadian rhythm (Garcia-Rodriguez et al. 1987), seasonal changes (Wolf et al. 1985), or plasma storing methods (Bustamante and Traviani 1993). The Bonelli’s Eagle {Hieraaetus fasciatus) is an endan- ^ E-mail address: Balbonja@ebd.csic.es gered species that has suffered a rapid population de- cline in most areas of Europe including Spain (Cugnasse 1984, Palma et al. 1984, Hallmann 1985, Arroyo et al. 1990). In this article, we present normal chemical plasma values found in a free-living endangered population of nestlings of this bird of prey. Data from 21 biochemical substances (including metabolites, total protein, inorgan- ic ions, and enzyme activities) and differences found be- tween sexes in this age-class are reported. In addition, we have examined the differences found between free-living and captive birds of this long-lived raptor. Methods We have studied a breeding population of Bonelli’s Ea- gles in the province of Cadiz that is located in southern Spain (5°32'W, 36°41'N). We collected blood from both nestlings of a free-living population of south Spain and from captive young Bonelli’s Eagles. The diet of eagles in our region included a preponderance of rabbits {Or- yctolagus cuniculus), and Red-legged Partridge (Alectons rufa) (Gil-Sanchez et al. 1994, Ontiveros and Pleguezue- los 2000) . Birds kept in captivity were fed ad libitum with partridge and rabbit. Blood collected from free-living nestlings was taken when individuals were between 47- 53-d-old, about 10 d before fledging. One of us climbed or descended to several nests each year to band and mea- sure young; at the same time 2 ml of blood was extracted from the brachial vein of the wing. To minimize circadian variations of blood parameters, we extracted all blood samples between 1100-1500 H. CST blood was collected in lithium-heparin tubes and the plasma was separated by centrifugation (10 min: 907.2 X g). Cellular fraction and plasma samples were immediately frozen ( — 80°C) Analyses were carried out 4 mo later with a Hitachi 747 multichannel automatic analyzer (Tokyo, Japan) with the reagents recommended by Boehringer-Mannheim (Darmstadt, F.R.G). Plasma was analyzed (abbreviations and methods indicated in parentheses) for amylase (AMY; maltoheptaose reaction), cholesterol (CHOL; cholesterol esterase), creatinine (CREA; Kinetic Jaffe re- action), creatinine kinase (CK; optimal standard method DGKC), glucose (GLUC; hexokinase method), aspartate aminotransferase (AST; DGKC technique), alanine ami- notransferase (ALT; DGKC technique), total protein (TP. biuret reaction), triglycerides (TRIG; enzymatic meth- od), urea (UREA; urease method, uric acid (UA, uricase method), alkaline phosphatase (AP; paranitrophenyl- phosphate method), colinesterase (CHE), L-lactate de- hydrogenase (LDH; SFBC technique), bilirubin (BILIR; DPD method), calcium (Ca; cresolphtalein complexone reaction), phosphorus (iP; molybdenum blue reaction), 231 232 Short Communications VoL. 36, No. 3 sodium (Na, Indirect potentiation, E. Selective) , potassi- um (K; Indirect potentiation, E. Selective), magnesium (Mg; blue xilidil reaction). The cellular fraction of the blood sample was used to sex all eagles. Eor this analysis, primers 2945F, c£R and 3224R were used following Ellegren (1996). The total number of eagles sampled included 28 nestlings, 14 fe- males and 14 males, belonging to a free-living population and two young males and three young females that were captive birds. We used the Student’s t-test to check for differences in the means of blood parameters between sexes and be- tween captive and free-living birds. Non-parametric tests were employed for those variables not meeting either normality or homoscedasticity assumptions (Siegel and Castellan 1988). When data were not normally distribut- ed, they were log^ transformed (Sokal and Rohlf 1995). After this transformation only two blood parameters AP and K, did not exhibit a normal distribution. The as- sumption of homoscedasticity was met for those param- eters showing a normal-like distribution. Levene’s F test was used to test for homoscedasticity. All tests were two- tailed and statistical significance was set at P < 0.05. Means are given with ±SD. Range for all variables are also provided. In some cases due to the small plasma volume of some samples, it was not possible to do anal- yses of all chemical parameters, thus, the sample size is not the same for all blood components. Analyses were performed with the Statistica Ax 99 package (Statistica. 1996. Version 5. StatSoft, Inc.). Results Normal reference plasma chemistry values for nestling Bonelli’s Eagles are shown in Table 1. We found differ- ences in parameters between male and female free-living nestlings in two of 21 plasma parameters measured. Males showed higher glucose levels in blood and lower AST activity than females (Table 1). We found that urea (t = 3.78, df = 32, P< 0.001), uric acid {t = 3.21, df = 33, P< 0.001), alkaline phosphatase (t = 3.52, df = 32, P < 0.001) and creatinine kinase (t = 2.5, df = 32, P< 0 05) values were lower than these measured in captive eagles. However, glucose {t = —3.89, df = 33, P< 0.001) was higher in captive compared with free-living birds. Discussion Our data showed that there were differences in plasma glucose levels between sexes in nestling Bonelli’s Eagles, males showing higher levels than females (Table 1). Polo (1995) failed to find any difference in this parameter between sexes in eight avian orders including Falconifor- mes. However, Polo (1995) only examined birds that were in captivity. Levels of glucose in plasma have been correlated with metabolic rate (Umminger 1977). Birds that showed a high metabolic rate, because of high activ- ity such as flying with fast flapping, would also have high- er levels of glucose in plasma. Bonelli’s Eagle exhibits a strong sexual size dimorphism, with females being much larger than males, which implies that male and female nestlings of this species would have different metabolic rates due to different growth patterns. Consequently, each sex may be exposed to a different energy demand during the nestling period. For example, female nestlings gain an estimated 7.3 grams more than males each day during the nestling period, which lasts on average be- tween 59 (Minguez et al. 2001) and 63 d (Real et al 1998). Therefore, males might have higher glucose levels because they have a lower growth energy demand than females. The larger females might channel more glucose into tissue formation than smaller males. Recently, Cas- ado et al. (2002) also found that male nestling Booted Eagles (Hieraaetus pennatus) had higher glucose than fe- males, another raptor with strong sexual size dimor- phism. However, Gonzalez and Hiraldo (1991) studying free-living nestling Marsh Harriers {Circus aeruginosus) (also shows sexual size dimorphism), found the reverse tendency with female nestlings having higher glucose lev- els than males. A possible explanation is that glucose lev- el in nestlings could indicate the quantity and quality of food received by each individual during the growing pe- riod. Parents might be able to allocate food in an asym- metric way within brood favoring either sex depending on environmental condition or food availability; for ex- ample, the larger or older sibling may receive more food in years of scarcity (Mock et al. 1987). As most of the knowledge in normal plasma reference values comes from captive birds, we compared blood chemistry values from our free-living nestling sample with values gathered from five juvenile captive eagles. These birds were young eagles in their first year; therefore, they were a few months older (less than a year different) than eagles sampled in nature. For this reason, age may have affected the differences found between these two groups Among the differences we found were those related to nitrogen residues. Captive birds had lower UREA and UA than free-living ones. These chemical constituents have been associated with physical condition in birds of prey. An increase in plasma levels of these nitrogen residues has been predicted when birds are subjected to a food stress situation (Ferrer 1994, Alonso-Alvarez and Ferrer 2001). Therefore, lower levels in UREA and UA in cap- tive birds indicate that these eagles were in better body condition than free-living birds. In this study we also found that captive eagles showed higher plasma glucose levels than free-living ones, which might be in accordance to what has been reported in other birds (Lewandoski et al. 1986, Casado et al. 2002). Captive individuals also showed lower CK activity than free-living ones. This enzyme mediates in muscle con- traction and is related with physical activity. Thus, it seems reasonable that eagles in captivity would show low- er CK activity than free-living eagles. The difference found on AP activity between captive and free-living birds might be attributed to an age effect rather than to a cap- tive condition since it is well known that the activity of this enzyme decreased with aged in birds of prey. Con- cretely, this enzyme is related to the ossification of frontal September 2002 Short Communications 233 a 'c3 a CO 'C^ a fi tT) Jh 'bb W V o eQ he Cl OJ C u fi T3 C d OJ 13 S u «5 u C I ■ < a > a u C3 u "C o s C3 t3 Q CO + 1 w H S HH CO w ►J > * J> nH o CO CM lO r' X r^ lO CM Oc CM o CD CO t^ q q t> lO CD q O) CM in CO X X X lO CO o CO cO d d d d d d d d d d o d d d d d d d d O d COiOCOCOOOiOOOGJiOGMcOinCM^ CM' CM ' — i CM I — I 1 — I CM i-h CM CM ^ CM CO CM CM CM O) cO'^'-H-M^CDcOiCjOr^iCiyOcOi^cOrtiiO'^-^t^'+i^ lOooio^oocD^aio^cDaicCi^CMCMiiO^^o^ CM o I o o o o I I I T— 1 o o I I r-l O O o I O O CM ^ Tti^Tt o 1-H CM m t-H o X t-H id CO c\i t^ lO CO GO CO l-H 1 1 i-H 1 CO 1 GO 1 CM 1 1-H 1 l—H cA m 1 CM 1 id 1 1-H 1 1 00 1 CM 1 00 1 C^l 1 J> 1 CO 1 CD 1 o 1 cr> 1 CD 1 * Oi • * CM CD X CM X CTi CM cO 1—1 o G\r CM " CO t- X 1-H GO (Ji J> o 4^ CO m 00 CM CO CM 00 00 CO CM CM I I I CM lO O CM ^ (>r I oo CO lO GO CD cr> CD H GO I I CT) CT) lO CD q X OD t^ O q X t> CM X CM 'cT CD X rH m m X rr q d J> o I— H X rH X CM CD rH m q hH 00 o d d X cd CM X CM rH CD GO d X d rH t-H d d d or> GO t-H + 1 + 1 +1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 +1 + 1 + 1 + 1 + 1 +1 +1 + 1 + 1 + ! + 1 X CM o q 1-H o O CM X X CO J> CM m CM o CD CM q 00 t-H o p ^H in CM p CM X id CM d CO X CM CM tT t-H t-H CD m X CO CM X m P rH X d q id CO -rH CM q CM q T— i q t-H cd o CM CO t-H in rH ■^GO-Tt^'^OOOCDCOGOCOCDGOtOlOlOCDJ>CDCOCOCr) ^_rf ^mmd o m J> 00 ^ ^ GO I I CO CO xo CM CO CO o ^ CO CM ^ CO CO O CO ^ CO ^ rn ^ ^ ^ q CM CO GO CO i> I I 1 I CO J> GO 00 j> o lO ^ cA CO OC CM O CO X ^ lO ^ ^ o T— 1 I O) X ^ . T-^ O 0^ 4 CM q I I IT) oc CO CM lO CM o CM I X X MO d d. CO GO ^ IT) o ti CO SD CD q CO m (D I> X q CO (D CM tH. X o X X o o o o 1 — 1 id o t> CM q rH m CM X CM t^ t-H q X q in P -f-l CM d CM p rH CO CM X X rH d X d 1-H ■^H d d d rH CM + 1 + 1 + 1 +1 +1 + 1 + 1 + 1 +1 + 1 +1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 t^ CM X X X rH X CD r^ in X t^ CD X m in CD q q in s t> id 1-H CM CM P X CO p CM d CM rH CM O) T-H rH Dh rH rH in X X 'cT O rH X P rH d O t-H 1-H t-H P 1-H H-1 h-1 'o "o s a a a 1 j h-i "o 'o a a ± ± I h-i I I I kJ I— 1 hJ H-1 'o \ he 'o 'o I k-1 'o hJ 'o I I bcdPDDDaaaaaaaa.pdp O P P u Probability that means are equal calculated with a Student’s Hest. Probability that distributions are equal calculated with a Mann-WTtitney U-test. Signihcantly different, P < 0.05. 234 Short Communications VoL. 36, No. 3 bones that take place throughout the immature to adult age period (Dobado-Berrios and Ferrer 1997, Vihuela et al. 1991). Resumen. — Este articulo presenta informacion sobre los valores de referenda normales de parametros bioquimi- cos presente en plasma sanguineo de polios estudiados en libertad de Aguila perdicera {Hieraaetus fasciatus). In- vestigamos diferencias en los parametros sanguineos en- tre sexos. Los machos muestran unos niveles mas altos de glucosa y una actividad enzimatica de Alanino-amino transferasa (AST) mayor que las hembras. Los polios fu- eron comparados con jovenes aguilas mantenidas en cau- tividad. Las aguilas cautivas tuvieron valores mas bajos de urea, acido urico, fosfatasa alcalina, creatinina quinasa y valores mas altos de glucosa que los polios marcados en libertad. [Traduccion de los autores] Acknowledgments We want to acknowledge the help of E. Minguez, J.R. Benitez, V. Siebering, C. Aguilar, J.A. Gil, and E. Saez in the field. We also thank E. Calvo for climbing to cliff nests. C.F. Vega and C. Alonso helped with blood analysis. 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Ceballos, andJ.A. DonAzar. 1998. Effects of age and captivity on plasma chemistry val- ues of the Egyptian Vulture. Condor 100:719-725. Ellegren, H. 1996. First gene on the avian W chromo- some (CHD) provides a tag for universal sexing of non-ratite birds. Proc. R. Soc. Lond. 263:1635-1641. Ferrer, M. 1993. Blood chemistry studies in birds: some applications to ecological problems. Pages 1031-1044 in S.G. Pandali [Ed.], Trends in comparative bio- chemistry and physiology. Council Scientific Research Integration, Trivandrum, India. . 1994. Nutritional condition of Spanish Imperial Eagle nestling {Aquila). Bird Study 41:120-123. , T. Garcia-Rodriguez, J.C. Carrillo, andJ. Cas- troviejo. 1987. Hematocrit and blood chemistry val- ues in captive raptors {Gyps fulvus, Buteo buteo, Milvus migrans, Aquila heliaca). Comp. Biochem. Physiol 87: 1123-1127. Garcla-Rodriguez, T, M. Ferrer, F. Rec:io, and J. Cas- TROVIEJO. 1987. 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Harrison [Eds.], Clinical avian medi- cine and surgery. W.B. Saunders Co. Philadelphia, PA U.S.A. Miglirioni, R.H., C. Linder, J.L. Moura, andJ.A. Veiga. 1973. Gluconeogenesis in a carnivorous bird (Black Vulture). Am. J. Physiol 225:1389-1392. Minguez, E., E. Angulo, and V. Siebering. 2001. Factors September 2002 Short Communications 235 influencing length of the post-fledging period and timing of dispersal in Bonelli’s Eagle (Hieraaetus fas- datus) in southwestern Spain. J. Raptor Res. 35:228- 234. Mock, D.W., T.C. Lamey, and B.J. Ploger. 1987. Proxi- mate and ultimate roles of food amount in regulating egret sibling aggression. Ecology 35:1760-1772. Ontiveros, D. and J.M. Pteguezuelos. 2000. Influence of prey densities in the distribution and breeding suc- cess of Bonelli’s Eagle {Hieraaetus fasdatus): manage- ment implications. Biol. Conserv. 93:19-25. Palma, L., F. Cancelada, and L. Oliveira. 1984. 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Received 31 December 2001; accepted 23 May 2002 Letters / Raptor Res. 36(3);236-237 © 2002 The Raptor Research Foundation, Inc. The Fox Kestrel (Falco alopex) Hovers Although typically considered related and similar to other kestrels {Falco spp.), the little-known, Sahel-endemic Fox Kestrel {Falco alopex) seems to exhibit some unusual morphological traits and behaviors. Reports have been particu- larly contradictory concerning the hovering ability of this species. For example, “Is misnamed ‘kestrel’ as has few kestrel-like habits. Normally, in open country perches on trees, and catches prey by short swoop from perch to ground; does not hover. In general behaviour more a long-winged, long-tailed falcon than kestrel.” (Brown et al. 1982, The birds of Africa, Vol. 1, Academic Press, London, U.K.), or “. . . long narrow pointed wings and, for falcon, excep- tionally long graduated tail giving atypical kestrel shape, more like long-tailed hobby” and “Rarely, if ever, hovers” (Ferguson-Lees and Christie 2001, Raptors of the world, A&C Black, London, U.K.). Another description is “Long, broad wings and graduated tail suggest buoyant flight and good hovering ability” (del Hoyo, J., A. Elliott, andj. Sargatal [Eds.]. 1994, Handbook of the birds of the world. Vol. 2. Lynx Edicions, Barcelona, Spain). A buoyant, slow flight mode was previously hypothesized by Cade (1982, The falcons of the world, Cornell Univ. Press, Ithaca, NY, U.S.A.), who added that “certainly more observations are needed before one can be sure about all of its hunting and flying characteristics.” Hovering occurs in distantly-related raptors, including in some Falconidae and some Accipitridae, certainly as a result of convergent evolution. However, hovering has been used as a behavioral trait indicating phylogeny (Boyce and White 1987, Pages 1-21 in D.M. Bird and R. Bowman [Eds.], The ancestral kestrel,/. Raptor Res. Rep. No. 6). Specifically, hovering is thought to be a derived trait. Thus, Boyce and White (1987) suggested that the Eox Kestrel was a primitive kestrel based on the reported absence of hovering. On 16-17 August 2001, during a visit to the Mandara Mountains, Cameroon, I observed a pair of these falcons hunting over pastureland near the village of Roumsiki (1100 masl). During my observations, performed in late afternoon and early morning, the sky was clear and the falcons’ activity seemed stimulated by a light breeze on the grassy slopes. The kestrels were actively soaring and gliding. The latter flight behavior seemed much slower and steadier than that of a Eurasian Kestrel {Falco tinnunculus) . The flight of the Fox Kestrels gave the appearance of miniature Lammergeiers {Gypaetus barbatus). After hanging in the wind at 5-10 m above the ground (stationing), the falcons were able to hold their position with minimal, compensative movements of the wings and tail. Occasionally, the falcons beat their wings obviously (hovering). Once prey was located, the kestrels descended at an angle, slowly and continuously (with no diving or descent hesitations). The birds did not stay on the ground, but the prey (probably orthopterans) was consumed in the air. I videotaped flight sequences of Fox Kestrels for later comparison with Eurasian Kestrels under similar conditions as far as weather, terrain, and prey involved (orthopterans) are concerned. A 5-min hunting sequence of one Fox Kestrel gave the following results: 4 stationings in the air, 2 with and 2 without hovering; 6 hovering bouts, with a mean of 2-2 ±1.2 (SE) wing beats/bout; and 4 descents to the ground. Eilming of a Eurasian Kestrel in Italy during a 5-min period revealed the following results; 11 stationing bouts, 8 with and 3 without hovering; 15 hovering bouts, with a mean of 7.3 ± 9.3 (SE) wing beats/bout; and 2 descents to the ground. Analysis of direct flights revealed similar wing beat frequencies for both Fox and Eurasian kestrels (near 6/sec), and the positions of wings and tails during soaring and gliding were also similar. Although Africa may well have been an important site for kestrel radiation, the suggestion that the Eox Kestrel might be the most primitive of the typical kestrels (Boyce and White 1987) seems unlikely. Provided that hovering has some phylogenetic value, finding it infrequent in a species may suggest either the incipient or the reduced trait. Coupling the variation of hovering among falcon species with that of unrelated traits may solve this problem of evolutionary direction as well as help clarify the relationships of falcons. In adulthood, the Pox Kestrel has an un- usually pale eye similar to the Greater Kestrel {F'alco rupicoloides) , its probable closest relative (Olsen et al. 1989, Emu 89.193-203). Erom photographs (Kemp and Kemp 1998, Sasol birds of prey of Africa and its islands, New Holland, London, U.K.); it seems that the juvenile Fox Kestrel has paler eyes (different than in adults) than the Juvenile Greater Kestrel. The latter has decidedly dark eyes like most falcons and all the Old World falconets (often considered primitive falcons) at any age. For this reason the Greater Kestrel, with more tinnunculus-\\k.e proportions and flight behavior (more frequent hovering), might be a transitional form from the Eurasian to the Fox Kestrel rather than the reverse. At first sight, the extremely developed wings and tail of the Fox Kestrel may suggest the Eleonora’s Falcon 236 September 2002 Letters 237 (Falco eleonorae), also a candidate for an ancestral falcon (Olsen et al. 1989). However, the wings and tail of the Fox Kestrel have a narrower base, as if resulting from a distal enlargement of gracile structures of tinnunculusA\k.€: ances- tors. Thus, the Fox Kestrel may be less an atypical kestrel than usually assumed. Also, I suggest that the infrequent hovering of Fox Kestrels can be explained. This kestrel may have departed from more tinnunculu&-\\kc birds through specialization to inexpensive, slow flight for hunting small, scattered, and not very mobile prey in dry savannahs. The suggested resemblance, size apart, with the Lammergeier may represent convergent evolution toward the ability to remain on the wing for long periods in order to hunt broken terrain. I thank J.C. Bednarz, W.S. Clark, and S.K. Sherrod for useful suggestions. — Tiziano Londei, Dipartimento di Biol- ogia, Universita degli Studi, Via CeLoria 26, 20133 Milano, Italy; e-mail address: londeit@tin.it Received 13 November 2001; accepted 11 March 2002. J. Raptor Res. 36(3) :237-238 © 2002 The Raptor Research Foundation, Inc. Probable Breeding oe Short-eared Owls in Southern West Virginia During spring and summer of 2001, we observed adult and juvenile Short-eared Owls {Asio flammeus) frequenting grassland habitats of three reclaimed mine sites in Logan, Fayette, Kanawha, and Boone counties in southern West Virginia. This species has been previously reported as an uncommon migrant or winter visitant in West Virginia (Hall 1983, West Virginia birds, Special Publication Carnegie Museum of Natural History No. 7, Pittsburgh, PA U.S.A); however, there are no breeding or nesting records in the state (Bnckelew and Hall 1994, The West Virginia breeding bird atlas. Univ. of Pittsburgh Press, Pittsburgh, PA U.S.A., Holt and Leasure 1993, in A. Poole and F. Gill [Eds ], The birds of North America No. 62, The Academy of Natural Sciences, Philadelphia, PA U.S.A.). Our sightings lend snpport to the idea that Short-eared Owls are opportunistic and will colonize areas when the conditions are suitable. Eight different adult female and three different adult male Short-eared Owls were observed multiple times on or near reclaimed grassland areas. They were identified as different individuals based on their repeated occurrence in specific areas of each mine. Sex determination was based on observed plumage pattern differences (Sibley 2000, Alfred A. Knopf, Inc. New York, NYU.S.A.). Observation dates ranged from 14 March-13 July 2001, with sightings occurring between 0545 and 1130 H, and 1630 and 2000 H EST. The owls were observed in a suite of behavioral contexts. Most were observed flying low over grassland habitat actively foraging. One individual male was observed in an acrobatic aerial display with a male Northern Harrier (Circus cyaneus). A very vocal female was observed on the ground consuming an unidentified mammalian prey item. Several individuals were observed perched on large rocks Two juvenile Short-eared Owls were observed flying low over grassland areas on two separate mine sites in Logan and Boone counties on 11 June 2001 and 19 June 2001, respectively. On each occasion, juveniles were closely accom- panied by an adult female. In one case, the juvenile was following a female that was hunting and capturing prey. Juvenile plumage patterns were similar to the adults with more black on the facial disks and tawny feather tips. The time of year that the juveniles were present and the lack of suitable habitat elsewhere in this region, strongly suggests that these individuals fledged from nests on the mine sites. Typical breeding dates for this species range from mid- April to June in most years (Mikkola 1983, Br. Birds 65:453-460). Short-eared Owls prefer to forage and nest in open habitats such as old fields, hay meadows, pastures, prairies, dunes, and marshes (Johnsgard 1988, Smithsonian Institution Press. Washington, DC U.S.A.). Mountaintop mining valley fill (MTMVF) practices in West Virginia convert large areas of mature hardwood forest to early successional habitats consisting of low- to medium-height grassland plant communities. The three reclaimed MTMVF mine sites on which owls occurred included expansive networks of contoured grassland habitat (ca. 1600-2000 ha at each site) that ranged in age from 5-19 yr old. Reclaimed sites are dominated by a mixture of grasses and forbs (native and non-native) with scattered shrub/seedlings of autumn olive (Elaeagnus umbellata), black locust (Robinia pseudoacaaa) , and European black alder (Alnus glutinosa) . These areas support dense small mammal populations that include white- footed mice (Peromyscus leucopus), deer mice (Peromyscus maniculatus) , southern bog lemmings (Synaptomys coopen), and meadow voles (Microtus pennsylvanicus) (Chamblin 2002, M.S. thesis, West Virginia University). These species along with an abundant grassland bird assemblage dominated by Grasshopper Sparrows (Ammodramus savannaruni ) , Eastern Meadowlarks (Sturnella magna), Horned Larks (Eremophila alpestris), and Killdeer (Charadrius vociferus) appar- ently provide an adequate prey base for Short-eared Owls on these sites. 238 Letters VoL. 36, No. 3 The North American breeding distribution of Short-eared Owls ranges from western Alaska east through Canada to Newfoundland, south to central California, and east across the north-central states to Newjersey (Johnsgard 1988) Holt and Leasure (1993) indicate that this species occurs year-round north and west of West Virginia while northern breeding populations are migratory. Our observations and accounts from others suggest that this species may be expanding its range along the southern edge of the previously reported North American breeding range. Several accounts have confirmed Short-eared Owl presence and breeding on coastal grassland habitats in Virginia, Maryland, and North Carolina (lliff 2001, N. Am. Birds .5.5:284-287). Besides West Virginia, Short-eared Owl breeding also has been documented on reclaimed mine sites in Kentucky (Stamm and Clay 1989, Kentucky W«rWer 65:75-76); however, breeding populations appear to be restricted to a few larger reclaimed areas (Palmer-Ball et al. 1990, Kentucky Warbler 66:73-80). This species exhibits some degree of nomadism with fairly long-distance movements by juveniles and adults (Clark 1975, Wildl. Monogr. 47:1-67, Cramp 1985, Oxford Univ. Press, Oxford, UK, Mikkola 1983, Br. Birds 65:453- 460). Such behavior undoubtedly contributes to the ability of Short-eared Owls to find and colonize the newly-created grassland habitats in eastern states, allowing an expansion of the breeding range. This range expansion may be temporary, however, after succession renders these sites unsuitable for Short-eared Owls. — Frank K. Ammer and Petra Bohall Wood, West Virginia Cooperative Fish and Wildlife Research Unit, BRD/USGS, and Division of Forestry, West Virginia University, P.O. Box 6125, Morgantown, WV 26506 U.S.A.; e-maU address: fammer@wvu.edu Received 5 December 2001; accepted 19 May 2002. Associate Editor: Ian G. Warkentin J Raptor Res. 36(3): 238-2.39 © 2002 The Raptor Research Foundation, Inc. Endangered Egyptian Vulture {Neophron percnopterus) Entangled in a Power Line Ground-wire Stabilizer Avian mortality is one of the highest environmental costs of power lines all around the world. Research has widely demonstrated the killing of thousands of birds in some regions, and power-line mortality has contributed to declines in some populations of rare species (see review in Ferrer, M. and G.F.E. Janss 1999, Birds and power lines. Ed Quercus, Madrid). Mortality on power lines is traditionally associated with two types of accidents: electrocution and collision (Janss, G.F.E. 2000, Biol. Conserv. 95:353-359). Electrocution occurs when the bird touches two wires or, more frequently, a wire and the grounded metallic pylon; in addition, collisions with overhead wires usually take place when visibility is low (at night or in foggy weather) and species involved are usually flocking birds, such as ducks or gulls (Ha.ss, D. 1980, Ecol. of Birds 2:117-157; Avian Power Line Interaction Gommittee [APLIC] 1996, Suggested practices for raptor protection on power lines: the state of the art 1996, Edison Electric Institute and Raptor Research Foundation, Washington, DG U.S.A.; Ferrer et al. 1991,/ Field Ornithol. 62:181-190). Here we describe a new type of accident in power lines, entanglement in power line ground-wire stabilizer. This has been suggested before: see Olendorff et al. 1981, Suggested practices for raptor protection on power lines: the state of the art 1981, /■ Raptor Res. Rep. 4:1-1 1 1 . We observed this type of entanglement in a 66 kw transmission line, property of Empresa Nacional de Electricidad, Sociedad Anonima (ENDESA), crossing the island of Fuerteventura (Ganary archipelago, Spain). On 10 November 2000, at dusk, we found a subadult Egyptian Vulture {Neophron perc- nopterus) with its right talon hooked up on a ground-wire stabilizer placed on one side of the power pole (Fig. 1) This individual probably perched on the stabilizer, as it is frequently observed among roosting individuals (see below) It could have caught its right talon in the lower hook-shaped structure, preventing escape. We rescued the bird the next morning; it was exhausted but still alive. Its ankle joint was seriously damaged. Gonsequently, it was necessary to amputate its talon. The bird was a 3-yr-old female. It had been captured using a cannon net in September 2000 as part of a population monitoring research program. The metallic ring on its right tarsus probably exacerbated the damage, as it hung from the stabilizer. Egyptian Vultures in Fuerteventura usually roost along the 30 km on this power line year round; up to 1 25 indi- viduals have been observed at one time with a maximum of 13 birds/pylon; ca. 96% of the total population on the island (Donazar et al. 2002, Biol. Conserv. 107:89-97). Electrocutions and collisions have been reported on the island, affecting Egyptian Vultures and other endemic and endangered avian species (Lorenzo, J.A. 1995, Ecologia 9:403- September 2002 Letters 239 Figure. 1. The immature female Egyptian Vulture entangled in the stabilizer. 407; Lorenzo et al. 1997, Vieraea 26:1-10). Hooking in stabilizers was never observed before, although vultures often roost in these structures (36.9% of the individuals roosting in pylons perch on stabilizers, N = 384, unpubl. data). It cannot be discarded, however, that some injured birds may escape after entangling. In fact, during 2001 we have observed four free-ranging individuals with fractured legs; another bird was missing a leg. Survival probabilities of these individuals would be consequently reduced. As the use of leg paddle traps is unknown on the island it seems reasonable to examine the role that entanglement may have in the occurrence of leg injuries. Finally, the Canarian population of this species is endemic to the archipelago (N. p. majorensis', Don^ar, et al. 2002,/. Raptor Res. 36:17- 23) and is extremely endangered (26 breeding pairs in 2001, Donazar et al. 2002). Casualties on power lines has caused the mortality of 14% of the extant Canarian Egyptian Vultures (16 cases of electrocution, 1 case of collision, and 1 case of entanglement) and represent an important risk to this population. This problem should also be considered in the design of power lines potentially used by large roosting birds in other regions of the world. We would like to thank the Consejeria de Medio Ambiente del Cabildo Insular de Fuerteventura and the Project REN 2000-1556 GLO that funded this research. We thank the staff of UNELCO-ENDESA for the assistance during the rescue of the bird. We also wish to thank Juan J. Negro, Jose A. Donazar, Fernando Hiraldo, Miguel Ferrer, and Robert M. Lehman for reviewing early drafts of this letter. — Laura Gangoso and Cesar J. Palacios, Department of Applied Biology, Estacion Biologica de Donana, C.S.I.G., Pabellon del Peru, Avda M“ Luisa s/n, 41013 Sevilla, Spain; e-maU address: laurag@ebd.csic.es Received 9 November 2001; accepted 3 May 2002. /. Raptor Res. 36(3):239-240 © 2002 The Raptor Research Foundation, Inc. Barred Forest-Falcon {Micrastur ruficollis) Predation on a Hummingbird Hummingbirds are widely regarded as having few predators away from the nest. However, incidental attacks upon hummingbirds by a number of bird species have been reported and may exert at least a moderate selective pressure. Wright (1962, Auk 79:112) reported a Baltimore Oriole {Icterus galbula) killing a Ruby-throated Hummingbird {Ar- 240 Letters VoL. 36, No. 3 chtlochus colubris). In addition, Brown-crested {Myiarchus tyrannulus) (Snider 1971, Am. Birds 25:780—784; Gamboa 1977, 94:157-158) and Gray flycatchers {Empidonax torightii) (Seutin and Apanius 1995, Wilson Bull. 107:565-567) have been observed to prey on hummingbirds. A Greater Roadrunner ( Geococcyx californianus) was observed catching hummingbirds at a feeder in Arizona (Spofford 1976, Connor 78:142). In contrast, it appears only a few raptors prey on hummingbirds. This might be because hummingbirds offer such small energy rewards for a large predator (Seutin and Apanius 1995) . Nevertheless, Merlins (Falco columbarius) have been observed chasing and catching hummingbirds successfully (Sprot 1927, Conrfor 29:71-72; Lowery 1938, Auk 55:280; Mayr 1966, Auk 83:664), and both Mayr (1966) and Balgooyen (1976, Univ. Calif. Publ. Zool. 103:1-83) observed American Kestrels {Falco sparverius) catching hum- mingbirds in the air. Also, Peeters (1963, Wilson Bull. 75:274) observed a Sharp-shinned Hawk {Accipiter striatus) catch an Anna’s Hummingbird ( Calypte anna) . Only two small raptors. Bat Falcons {Falco rufigularis) and Tiny Hawks {Accipiter superciliosus) , take large numbers of hummingbirds (Beebe 1950, Zoologica 35:69-86; Stiles 1978, Auk 95:550-553). Beebe (1950) estimated that 16% of a Bat Falcon’s diet consisted of hummingbirds, but he did not believe that these falcons had developed a specific hunting technique to catch hummingbirds. In contrast, Stiles (1978) suggested that Tiny Hawks are hummingbird specialists that employ three different techniques to catch hummingbirds. These tactics include still-hunting, waiting m ambush by a hummingbird’s territorial perch, and flying rapidly between several territorial hummingbird perches. We report here a capture of a hummingbird by a Barred Forest-Falcon {Micrastur ruficollis) . This forest-falcon used a tactic not reported before. The capture occurred at Loma Linda Botanical Gardens (00°01.62'S, 078°40.55'W) at ca. 2065 m elevation along the Old Nono-Mindo Road about 6 km west of village of Tandayapa in northwest Ecuador. The gardens comprise 30 ha and include abandoned pasture, secondary forest, and primary cloud forest. The capture occurred in part of abandoned cattle pasture where the first author maintains 30 hummingbird feeders, which daily attract 12-15 hum- mingbird species. The most common species at the Loma Linda feeders are: Green ( Colibri thalassinus) and Sparkling violet-ears (C. coruscans) , Western {Chlorostilbon mellisugus) and Andean emeralds {Amazilia franciae), Booted Racket- tails ( Ocreatus underwoodii) , White-bellied {Acesirura mulsant) and Purple-throated woodstars {Philodice mitchellii) , and Buff-tailed Coronets {Boissonneaua flavescens) . Most of the feeders at Loma Linda have an attendant (aggressive) hummingbird that keeps other hummingbirds away from their feeder. Although different hummingbird species guard feeders, a hierarchy of possession is evident. Western Emeralds and Booted Racket-tails guard their feeders, but rarely attempt to evict larger hummingbirds; the two woodstar species do not display territorial behavior. The most aggressive and successful at defending feeders are Sparkling Violet-ears, which is the largest and most common species at Loma Linda. Typically, Sparkling Violet-ears chase other hummingbirds for 3—10 m, before returning to a favored perch. In mid-June 2000, a Barred Forest- Falcon flew into a nearby tree at the edge of the abandoned pasture about 15 m from one of the guarded feeders and landed about 15-18 m up in the tree. The Barred Forest-Falcon stayed in the tree for 5-10 min, watching the hummingbirds before attacking one of the birds guarding a feeder. Rather than giving chase to the Sparkling Violet- ear, the raptor flew straight to the perch used by the hummingbird. As the violet-ear returned to its perch after chasing away another hummingbird from its feeder, the falcon intercepted and captured the hummingbird as it landed on its perch. The Barred Forest-Falcon then flew into an inga tree {Inga edulis), plucked out several of the hummingbird’s breast feathers, and fed. The hummingbird did not die immediately, but continued to flutter. After several minutes the forest-falcon flew off with the remains of the hummingbird. The attack by the forest-falcon suggests the bird anticipated the return of the hummingbird to its favored perch. Moreover, the kind of territoriality displayed by Sparkling Violet-ears and their habit of remaining perched in exposed, prominent locations adjacent to each feeder seems to make them especially vulnerable to interception. This intercept strategy appears nearly identical to the ambush strategy employed by Tiny Hawks (Stiles 1978), the only difference IS that the Barred Forest-Falcon did not move in close (2-3 m) to the perch (ambush strategy), but rather began its attack 20 m away. The behavior of the Sparkling Violet-ears suggests that all species of territorial hummingbirds might be susceptible to this type of attack, especially where large concentrations of feeders and hummingbirds occur. We thank Georgia Southern University for funding travel for Mark Welford and C. Ray Chandler for his comments on a first draft. — Tony Nunnery, Lomo Linda, Tandayapa Valley, Pichincha Province, Ecuador, and Mark R. Welford (corresponding author). Dept, of Geology and Geography, Georgia Southern University, Statesboro, GA 30460-8149 U.S.A.; e-mail address: mwelfgeog@gsvms2.cc.gasou.edu Received 15 July 2001; accepted 19 March 2002. BOOK REVIEWS J. Raptor Res. 36(3) ;241-242 © 2002 The Raptor Research Foundation, Inc. Raptors of the World. By James Ferguson-Lees and David A. Christie. 2001. Houghton Mifflin, Boston, MA. 992 pp., 4 tables, 60 figures, 112 color plates, numerous range maps. ISBN 0-618-12762-3. Cloth, $60.00 — For any birdwatcher enjoying a suc- cessful trip to a new country, few events are more frustrating than glimpsing an unknown raptor as it flies swiftly out of sight, never to be seen again nor identified with certainty. Diurnal raptors, whether perched or flying, are often difficult birds to iden- tify, even for experts. Fortunately, many regional field guides serve as excellent resources for raptor identification, yet no one has dared assemble a guide to all of the globe’s diurnal birds of prey. Raptors of the World aspires to accomplish this am- bitious goal. This enormous field guide is organized into a list of species, several chapters of natural history and identification information, color plates, de- tailed species descriptions, a bibliography, and an index. Following the species list, a brief Introduc- tion informs the reader that 313 species within four orders — Ciconiiformes (New World vultures) , Accipitriformes, Falconiformes, and Sagittariifor- mes — are recognized and treated within the text, departing from the standard treatment that places all diurnal raptors in the order Falconiformes. The next chapter, aptly titled Using This Book, de- scribes the general content and format of the color plates, distribution maps (in three colors distin- guishing migratory pathways and seasonal ranges) , and condensed caption texts that accompany the plates and maps. This chapter also contains a brief overview of topics included in each of the species accounts. Several chapters devoted to general identifica- tion cover bird topography, morphological mea- surements, and sex and age differences. The three pages of line drawings within the Raptor Topog- raphy chapter are well done and useful. Reversed sexual size dimorphism is treated in some detail and then related to identification, as are wingspan and total length measurements in the next chapter. Unlike traditional field guides on raptors, the book also includes lengthy chapters on migration, molt, and anatomy. A brief treatment of taxonomy and nomencla- ture completes the final two introductory chapters. The authors acknowledge that not all changes in taxonomy stemming from recent DNA-DNA hy- bridization studies could be incorporated into the book because of time constraints related to publi- cation. Thus, their classihcation remains conven- tional aside from the aforementioned division of the Falconiformes into four orders. Use of English names generally follows that proposed by the Brit- ish Ornithologists’ Union’s Records Committee, but North American buteos are still labeled “hawks” rather than “buzzards,” and “vulture” re- fers to taxonomically unrelated Old and New World species. In sum, the introductory materials encompass 79 pages. The most important parts of any field guide are the color plates, range maps, and species accounts. Raptors of the World contains an astounding 112 col- or plates that show 2115 individual birds, more than half of which are depicted in flight. The three artists — Kim Franklin, David Mead, and Philip Burton — illustrated adult and juvenile plumages of perched and flying individuals of each species. Most plates depict three species, but some wide- ranging species with variable plumage command several pages of artwork. The first three color plates categorize raptors by general size (large, medium, small) and distribu- tion (New and/or Old World) to help the unac- quainted birder narrow the bewildering array of species down to genus. Plates of species follow, each identically structured. Preceding the English name is a number corresponding to the list of spe- cies at the beginning of the book. Next are the scientific name and a page number referencing the species account in the main text followed by data on total length, wingspan, and tail length in centimeters (with the midpoint of the range in inches). Size of the male in proportion to the fe- male is given as a percentage. Opposite each spe- cies plate is a distribution map and condensed text describing overall appearance, flight characteris- tics, and aspects of general biology that may aid m 241 242 Book Reviews VoL. 36, No. 3 identification. A list of similar-looking species is ref- erenced by plate number. Extensive identification and natural history in- formation appear within the Systematics section, a chapter that spans a colossal 622 pages. At the top of each species account are repeated the English and scientific names and plate numbers. A large map in varying shades of gray accompanies the text and usually provides the same information illus- trated in the color maps. Distribution, behavior (e.g., migratory, breeding), habitat, food, and worldwide population are reviewed. Estimated size of the global population is categorized by numbers (1-7) that represent orders of magnitude (e.g., 5 = 10 001—100 000 individuals). The largest subsec- tion describes field characteristics, which are grouped by age, sex, geography, and size for both flying and perched birds. Characteristics helping to separate similar-looking species are also furnished. A list of references, abbreviated by author and year, completes each species description. The authors and artists completed a formidable project and succeeded in producing an attractive and useful book. However, preparing such a tome means it will be out-of-date and incomplete the moment it is published, mostly because of publi- cation deadlines rather than the authors’ inatten- tion to recent advances. Given that the primary purpose of the book is to serve as a field guide, I found most of the information in the opening chapters on natural history unrelated to identifi- cation and therefore unnecessary. Much of it was also dated, despite the 55-page bibliography. For example, the authors discuss reversed sexual size dimorphism at length, but an important paper on phylogenetic effects is not mentioned. The ability of raptors to see within the ultraviolet range also eludes discussion, and the role of ultraviolet plum- age characteristics is stated as unknown, but a wealth of literature chronicles these aspects of nat- ural history. I studied carefully the plates and text of all North American species, the group with which I am most familiar, and found several significant er- rors. The most noticeable and troublesome short- comings concerned the accuracy of the distribu- tion maps, which were produced by relying on previous books. For example, maps for Mississippi Kite (Ictinia mississippiensis) , Common Black-Hawk (Buteogallus anthracinus) , Crested Caracara {Cara- cara plancus), and Peregrine Falcon {Falco peregn- nus) either were poorly done or did not indicate large areas where these species occur. Although the authors ended literature reviews for most spe- cies in the mid-1990s, they should have examined some contemporary sources (e.g., the Birds of North America series) to update and verify distributions. A few of the plates also contained errors. For ex- ample, age-specific plumages of the Bald Eagle {Haliaeetus leucocephalus) , leg color of the Turkey Vulture {Cathartes aura), and color of the tarsus feathers of the Golden Eagle {Aquila chrysaetos) were incorrect. These errors were unsettling be- cause North American raptors are well known com- pared with species inhabiting remote parts of the globe. The style of the three artists also differed significantly, which, in my opinion, detracted from the consistency in plate presentation. Despite these errors, Raptors of the WorW deserves a place in the libraries of globetrotting birders who have a deep interest in and appreciation for rap- tors, simply because it provides so much informa- tion in an accessible format. The sheer bulk of this “field guide,” however, means that it will rest on a coffee table or bookshelf far more often than in- side a backpack. Ornithologists who venture abroad will also find it a handy reference when used in combination with regional field guides. Fi- nally, public and academic libraries certainly should include this book in their ornithological collections to complement texts that focus on rap- tor natural history. — Marco Restani, Department of Biological Sciences, St. Cloud State University, St. Cloud, MN 56301 U.S.A. f Raptor Res. 36(3):242-244 © 2002 The Raptor Research Foundation, Inc. The Spanish Imperial Eagle. By Miguel Ferrer. 2001. Lynx Edicions, Barcelona, Spain. 224 pp., 36 tables, 58 figures, numerous black-and-white pho- tographs. ISBN 84-87334-34-2. Cloth, $28.00— If you are interested in the behavior, population ecol- ogy, or conservation of raptors, then you must be- come familiar with this book. It is a quick and in- formative (although sometimes tedious) read that introduces you to one of the rarest raptors in the September 2002 Book Reviews 243 world. The chapters cover taxonomy, biometry and physiology; distribution and status; feeding; repro- duction; the dependence period; dispersal; mor- tality; population dynamics; population genetics; and conservation. The author draws on his 20 years of experience with Aquila adalberti in Dohana National Park to develop these topics and put them into a larger ornithological perspective. His stated objectives are to (1) present all up-to-date information on the species and (2) provide a thought-provoking basis for the conservation of Spanish Imperial Eagles. Ferrer accomplishes his first objective with a wonderful mix of photographs, line drawings, 36 data tables, and 57 graphs and maps. Methods and statistical analyses are summarized to aid your own interpretation of the results. As an indication of the types of analyses reported, consider these find- ings that I found most important: (1) blood chem- istry (especially urea, a possible indicator of con- dition) varies with age, hatching date, and many aspects of behavior; (2) using latex gloves while handling eagle chicks reduces staphylococcus in- fection; (3) apparent increases in reproductive suc- cess with breeder age are due to territory quality, not some inherent property of the pair; (4) terri- tory intrusion by immatures correlates positively with territory quality; (5) most of population re- newal is due to a few very productive pairs; (6) fledglings in poor nutritional condition remain in their natal territories longer and eventually dis- persed shorter distances than fledglings in good condition; (7) wind direction correlates positively with dispersal direction; (8) occasional observa- tions of subadults breeding, that we often dismiss as anecdotal, can in fact represent important pop- ulation-stabilizing mechanisms (as numbers de- cline, age of reproduction declines, which increas- es population growth, which reduces breeding by subadults); and (9) conservation efforts that re- duce juvenile and adult mortality are more likely to benefit the population than those aimed at aug- menting reproduction. The strongest part of the book reflects Ferrer’s primary expertise in the dispersal and develop- ment of independence by juvenile eagles. The 50 pages devoted to these topics are strong and well argued. I particularly liked the conceptualization of these two poorly understood phases of most birds’ lives. Dependence was divided into an early stage (fledgling to development of soaring flight) affected by the physical condition of the chick and a later stage (soaring flight to independence) pri- marily affected by the physical condition of the parent. Likewise, juvenile dispersal was divided temporally into phases of “local dispersal,” “first departure from the natal population,” “explora- tion,” “temporary settlement,” and “return to the natal population.” Such detailed investigation of mobile, wide-ranging birds with clear links between behavioral changes and important mechanisms is especially noteworthy. I was troubled by the shallow depth of treatment other topics received. There was little quantitative assessment of habitat use or habitat needs of the species. Certainly this should have been a corner- stone of investigation for such a rare species. No rigorous assessment of range contraction was pro- vided (maps are presented but are not tied to hab- itat changes, habitat quality, configuration, etc.). Despite a rather strong dependence hinted at be- tween rabbits and eagles, no quantitative measures of prey were provided, and no attempts were made to link eagle population dynamics with those of their prey. The behavior of eagles is described, but there are no quantitative presentations of time budgets or relative importance of foraging styles. We are not given a complete picture of how this eagle spends a typical day. Sociality is not men- tioned. Home-range dynamics and use of space by breeders are dealt with only superficially. The chapter on population genetics is only five pages long. The certainty of some findings is also presented a bit too strongly for my taste. For example, Ferrer claims that males and females can be distinguished “with certainty” by morphology, yet he shows that the sexes overlap in all physical characteristics. He also asserts that urea concentrations in the blood indicate the nutritional state of individual birds, but he does not discuss the potential problems with drawing this conclusion. I am not an expert in this area and found the correlations between urea and behavior exciting. However, upon dis- cussing this with several more-knowledgeable col- leagues, I found that although urea concentration does reflect protein catabolism and/or degrada- tion that can come from the individual or from its diet, it is tricky with a carnivorous bird to confi- dently identify the source of variation in the values. Ferrer should have discussed these uncertainties more openly. The biggest failure of this book is that Ferrer makes no attempt to put the work on Spanish Im- 244 Book Reviews VoL. 36, No. 3 perial Eagles into the broader context of behavior, ecology, and endangered species conservation. The literature cited is badly dated and heavily skewed toward raptors. Few articles (other than the author’s own) beyond 1990 are cited. This may not bother the ardent raptor biologist, but the impor- tance of this story for avian conservation and ecol- ogy in general will be lessened by this shortcoming. Lynx Edicions has attractively packaged this book and done a splendid job reproducing the fig- ures and photographs. However, they have done a poor job in proofreading and finalizing the text. On average, one typo occurs on every page, as do misalignments that confuse some of the tables. Many of the errors stem from translation into En- glish, for which the author and publishers have my sympathy. However, a quick proofing by someone proficient in English would have cleaned up 90% of these issues. Despite these drawbacks, Ferrer has provided a thought-provoking basis for conservation of Span- ish Imperial Eagles. However, I am not convinced that he has provided an action-provoking basis, and in my opinion that is what is really needed. He has armed those interested in raptor conservation with relevant biological information and shown clearly that simply reducing the risk of electrocu- tion will likely benefit the species. However, he has not given us any insights into the Spanish political system nor any indication of the likelihood that the Spanish people will embrace the changes needed to save this species. We all know that biology is only one side of the conservation equation; social, eco- nomic, and political considerations will always be important. As biologists, we must understand all of these dimensions to effectively enter into action- provoking discussions with policy makers, manag- ers, and planners. In summary, this is a classic case study of an im- periled raptor. Those interested in large raptors, especially eagles, will find it required reading. Those interested in conservation will do well to study the last chapter. Behavioral ecologists and population biologists will find important data to relate to their own studies. It belongs on library shelves, but not on the shelf of every ornitholo- gist. — John M. Marzluff, College of Forest Re- sources, University of Washington, Seattle, WA 98195 U.S.A. A Telemetry Receiver Designed with The Researcher in Mind What you've been waiting for! Finally, a highly sensitive 999 channel synthesized telemetry receiver that weighs less than 13 ounces, is completely user programmable and offers variable scan rates over all freguencies. 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The first seven volumes of this projected sixteen- volume work have been published, including Volume 2, covering the diurnal raptors, and Volume 3, covering owls. They are priced at $185 each. The Raptor Almanac: A Comprehensive Guide to Eagles, Hawks, Falcons, and Vultures. Scott Weidensaul. Lyons Press, 2000. 382 pp. Color photos. Cloth. $40.00 The Harris Hawk: Management, Training and Hunting. Lee W. Harris. Swan Hill Press, 2001. 144 pp. Color and b&w photos and illustrations. Cloth. $32.95 Rare and Out-of-print Falconry Usually available from Buteo Books, the classic reference on diurnal raptors; Brown & Amadon: Eagles, Hawks and Falcons of the World. First English edition, 1968. $300. Birds of North America series individual species accounts for Swallow-tailed Kite White-tailed Kite Snail Kite Mississippi Kite Bald Eagle Northern Harrier Sharp- shinned Hawk Cooper’s Hawk Northern Goshawk Common Black-Hawk Harris’ Hawk Red-shouldered Hawk Broad-winged Hawk Swainson’s Hawk White-tailed Hawk over 500 species, including: Zone-tailed Hawk Hawaiian Hawk Red-tailed Hawk Ferruginous Hawk Crested Caracara American Kestrel Merlin Gyrfalcon Prairie Falcon Bam Owl Flammulated Owl Eastern Screech-Owl Whiskered Screech-Owl Great Homed Owl Snowy Owl Northern Hawk Owl Northern Pygmy-Owl. Fermginous Pygmy-Owl Elf Owl Burrowing Owl Spotted Owl Barred Owl Great Gray Owl Long-eared Owl Short-eared Owl (R) Boreal Owl Northern Saw- whet Owl Available soon: American Kestrel California Condor 2003 ANNUAL MEETING The Raptor Research Foundation, Inc. 2003 annual meeting will be held on 2-6 September 2003 in Fairbanks, Alaska. For information about the rneebng see the following website: http://www.alaskabird.org or contact Nancy DeWitt (birds@alaskabird.org). Persons interested in predatory birds are invited to join The Raptor Research Foundation, Inc. Send requests for information concerning membership, subscriptions, special publications, or change of address to OSNA, P.O. Box 1897, Lawrence, ‘ kS 66044-8897, U.S.A. The Journal of Raptor Research (ISSN 0892-1016) is published quarterly and available to individuals for $33.00 per year and to libraries and institutions for $50.00 per year from The Raptor Research Foundation, Inc., 14377 1 l7th Street South, Hastings, Minnesota 55033, U.S.A. (Add $3 for destinations outside of the continental United States.) Periodicals postage paid at Hastings, Minnesota, and additional mailing offices. POSTMASTER: Send address changes to The Journal of Raptor Research, OSNA, P.O. Box 1897, Inwrence, KS 66044-8897, U.S.A. Printed by Allen Press, Inc., Lawrence, Kansas, U.S.A. Copyright 2002 by The Raptor Research Foundation, Inc. Printed in U.S.A. 0 This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). Raptor Research Foundation, Inc., Awards Lifetime Achievement Awards The Tom Cade Award recognizes an individual who has made significant advances in the area of captive prop- agation and reintroduction of raptors. Nomination packets can be submitted at any time. Contact: Brian Walton, Predatory Bird Research Group, Long Marine Laboratory, University of California, Santa Cruz, CA 95064 U.S.A.; tel. 408-459-2466; e-mail: walton@cats.ucsc.edu. The Fran and Frederick Hamerstrom Award recognizes an individual who has contributed significantly to the understanding of raptor ecology and natural history. Nomination packets can be submitted at any time. Con- tact: Dr. Clint Boal, Texas Cooperative Fish and Wildlife Research Unit, BRD/USGS, Texas Tech University, 15th Street & Boston, Ag Science Bldg., Room 218, I.ubbock TX 79409-2120 U.S.A.; tel. (806) 742-2851; e-mail: cboal@ttacs.ttu.edu. Student Recognition and Travel Assistance Awards The James R. Koplin Travel Award is given to a student who is the senior author and presenter of a paper or poster to be presented at the RRF annual meeting for which travel funds are requested. Contact: Dr. Patricia A. Hall, 5937 E. Abbey Rd. Flagstaff, AZ 86004 U.S.A.; tel. 520-526-6222; e-mail: pah@spruce.for.nau.edu. Application Deadline: due date for meeting abstract. The William C. Andersen Memorial Award is given to the students who are senior authors and presenters of the best student oral and poster presentation at the annual RRF meeting. Contact: Laurie Goodrich, Hawk Mountain Sanctuary, 1700 Hawk Mountain Road, Kempton, PA 19529 U.S.A.; tel. 610-756-6961; email: goodrich@hawkmountain.org. Application Deadline: due date for meeting abstract; no special application is needed. Grants For each of the following grants, complete applications must be submitted to the contact person indicated by 15 February. Recipients will be notified by 15 April. The Dean Amadon Grant for $200-400 is designed to assist persons working in the area of distribution and sys- tematics (taxonomy) of raptors. Contact: Dr. Carole Griffiths, 251 Martling Ave., Tarrytown, NY 10591 U.S.A.; tel. 914-631-2911; e-mail: cgriff@liu.edu. The Stephen R. Tully Memorial Grant for $500 is given to support research, management, and conservation of raptors, especially to students and amateurs with limited access to alternative funding. Contact: Dr. Kim Titus, Alaska Department of Fish and Game, Division of Wildlife Conservation, P.O. Box 240020, Douglas, AK 99824 U.S.A.; e-mail: kimt@frshgame. state. ak.us. The Leslie Brown Memorial Grant for up to $1,000 to support research and/or dissemination of information on birds of prey, especially to proposals concerning African raptors. Contact: Dr. Jeffrey L. Lincer, 9251 Golondrina Dr., La Mesa, CA 91941 U.S.A.; e-mail: jefflincer@tns.net.